Bio

Clinical Focus


  • Radiation Oncology
  • Stomach Cancer - Radiation Oncology
  • Pancreatic Cancer
  • Cancer > GI Oncology
  • Esophageal Cancer - Radiation Oncology
  • Rectal Cancer - Radiation Oncology
  • Liver Cancer - Radiation Oncology
  • Colorectal Cancer - Radiation Oncology
  • Pancreatic Cancer - Radiation Oncology
  • Cancer > Radiation Oncology

Academic Appointments


Professional Education


  • Internship:Kaiser Permanente/Santa Clara (1997) CA
  • Stanford University School of Medicine (1994) CA
  • Residency:Stanford University School of Medicine (2001) CA
  • Medical Education:Northwestern University Medical School (1996) IL

Research & Scholarship

Current Research and Scholarly Interests


Hypoxia induces endoplasmic reticulum (ER) stress in solid tumors. Previous studies have indicated that hypoxia is a major determinant of local, regional, and distant recurrence after anticancer therapy. The response of tumor cells to hypoxia depends on the severity and duration of oxygen deprivation. For example, hypoxia induced factor (HIF-1) is activated at physiological levels of oxygen change, whereas the unfolded protein response (UPR) is induced by severe oxygen deprivation. The UPR is an evolutionarily conserved pathway that functions to reduce protein accumulation in the ER resulting in increased capacity to tolerate ER stress. We hypothesize that since the UPR is also activated during hypoxia, it may be a critical regulator of cell survival during hypoxia and is necessary for tumor growth. The focus of my laboratory is to understand the relationship between hypoxia and ER stress, particularly as it relates to tumorigenesis.

Clinical Trials


  • Phase I/II Intratumoral DC Immunotherapy With Gemcitabine & XRT in Unresectable Pancreatic Cancer Not Recruiting

    To determine the safety, feasibility and appropriate dendritic cell dose to vaccinate patients with pancreas cancer

    Stanford is currently not accepting patients for this trial. For more information, please contact Jenna Rogers, (650) 723 - 4467.

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  • Feasibility of Using Real-time Cine-MRI for Treating Moving & Deforming Tumors Not Recruiting

    This study aims to investigate and optimize imaging sequences and parameters of rapid real-time MRI in order to obtain adequate guidance for accurately and precisely delivering radiation to moving abdominal and thoracic tumors.

    Stanford is currently not accepting patients for this trial. For more information, please contact Melody Chung, (650) 736 - 0798.

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  • Combination SBRT (Stereotactic Body Radiotherapy) With TACE (Transarterial Chemoembolization) for Unresectable Hepatocellular Carcinoma Not Recruiting

    To establish the efficacy and toxicity of TACE combined with SBRT

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Ann Columbo, 650-736-0792.

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  • Phase II Gemcitabine + Fractionated Stereotactic Radiotherapy for Unresectable Pancreatic Adenocarcinoma Not Recruiting

    This multi-institutional trial aims to evaluate the potential benefit and side effects of adding fractionated stereotactic body radiotherapy/surgery (SBRT) before and after chemotherapy with gemcitabine for locally advanced pancreatic cancer.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Ann Columbo, 650-736-0792.

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  • Transarterial Chemoembolization vs CyberKnife for Recurrent Hepatocellular Carcinoma Not Recruiting

    Primary Objective: To compare the efficacy of TACE vs. CyberKnife SBRT in the treatment of locally recurrent HCC after initial TACE. Secondary Objectives: 1. To determine the progression-free survival of TACE vs. CyberKnife SBRT 2. To determine the overall survival of TACE vs. CyberKnife SBRT for locally recurrent HCC 3. To determine the toxicities associated with TACE or CyberKnife SBRT for the treatment of recurrent HCC.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Ann Columbo, (650) 736 - 0792.

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  • PII of SBRT & Chemo for Unresectable Cholangiocarcinoma Followed by Liver Transplantation Not Recruiting

    The purpose of this study is to determine progression-free survival at 12 months for stereotactic body radiotherapy (SBRT) and chemotherapy for unresectable hilar cholangiocarcinoma (CCA). Investigators hope to learn more about neoadjuvant SBRT and chemotherapy for unresectable CCA, and if SBRT followed by chemotherapy can lead to successful liver transplantation. This knowledge is important for this patient group as this disease is a highly lethal malignancy that often presents as unresectable, however surgery or transplantation are the only curative options.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Ann Columbo, (650) 736 - 0792.

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  • Phase I/II PTK787/ZK 222584 and Gemcitabine in Advanced Pancreatic Cancer Not Recruiting

    The purpose of the study is to determine the optimal safe and tolerable dose of gemcitabine in combination with once daily or twice daily dose of PTK/ZK in patients with unresectable pancreatic cancer. The Phase II part of this trial plans to determine the antitumor activity of this regimen and its effectiveness of preventing tumor growth and spread.

    Stanford is currently not accepting patients for this trial. For more information, please contact Heidi Kaiser, (650) 724 - 0079.

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  • S0809: Capecitabine, Gemcitabine, and RT in Patients w/Cholangiocarcinoma of the Gallbladder or Bile Duct Not Recruiting

    RATIONALE: Drugs used in chemotherapy, such as capecitabine and gemcitabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. Giving more than one drug (combination chemotherapy) together with radiation therapy may kill more tumor cells. PURPOSE: This phase II trial is studying how well giving capecitabine together with gemcitabine followed by capecitabine and radiation therapy works in treating patients with cholangiocarcinoma of the gallbladder or bile duct.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laura Gable, (650) 736 - 0798.

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  • Prognostic Value of Baseline Computed Tomography (CT) Perfusion Parameters of Pancreatic Cancer for Patients Undergoing Stereotactic Body Radiotherapy or Surgical Resection Not Recruiting

    The purpose of this study is first, to determine whether baseline perfusion characteristics of pancreatic cancer, as characterized by CT perfusion studies, can predict tumor response to treatment by stereotactic body radiotherapy (SBRT). The second goal of this study is to determine whether baseline perfusion characteristics in those patients with resectable pancreatic cancer correlate with immunohistologic markers of angiogenesis such as microvessel density and vascular endothelial growth factor (VEGF) expression.

    Stanford is currently not accepting patients for this trial. For more information, please contact Lindee Burton, (650) 725 - 4712.

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  • Novel Serum Markers for Monitoring Response to Anti-Cancer Therapy Recruiting

    The purpose of this trial is to collect blood serum from cancer patients with tumors at different disease sites (such as pancreas, head and neck, and breast) prior to and at subsequent points following anti-cancer therapy to discover novel serum markers of response.

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  • QOL & Functional Outcomes After Combined Modality Tx for Anal CA: Comparison of Conventional vs IMRT Not Recruiting

    The purpose of this study is show that intensity-modulated radiotherapy (IMRT), as compared with conventional radiotherapy, improves the precision of tumor targeting and reduces the acute and late effects of radiation toxicity when used to treat anal cancer. Results from this work will provide a basis for incorporating the use of IMRT to treat anal cancer in future treatment protocols.

    Stanford is currently not accepting patients for this trial. For more information, please contact Moe Jalali, (650) 724 - 4023.

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  • Tissue and Plasma Biomarkers of Lymph Node Involvement in Cervical Cancer Recruiting

    SPECIFIC STUDY AIMS Specific Aim 1: To use gene expression analysis of primary cervical cancers to identify a gene expression signature that predicts for lymph node metastases in this disease. Specific Aim 2: To predict lymph node metastases by performing multiplex measurements of cancer-associated proteins and cytokines using proximity ligation assay (PLA) on plasma samples. Specific Aim 3: To measure circulating human papilloma virus (HPV) DNA in the plasma samples of cervical cancer patients using real-time quantitative polymerase chain reaction (qPCR) and determine its ability to predict for nodal metastases. Specific Aim 4: To use deep sequencing to evaluate gene and sequence differences between cervical cancer patients with and without lymph node metastasis.

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  • Phase I Trial of Metabolic Reprogramming Therapy for Treatment of Recurrent Head and Neck Cancers Recruiting

    To determine the maximum tolerated dose of DCA in patients with recurrent head and neck cancer who have failed first-line therapy. The purpose of this study is to study the effect of the drug DCA (dichloroacetate) on recurrent head and neck cancers. Part of this study will also use EF5 PET scan to study tumor hypoxia.

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  • Trilogy Stereotactic Body Radiotherapy for Pancreatic Cancer Not Recruiting

    This study will assess the efficacy of treating locally advanced pancreatic cancer using a linear accelerator designed for image-guided radiotherapy

    Stanford is currently not accepting patients for this trial. For more information, please contact Jeff Kim, (650) 498 - 7703.

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  • Safety Study of Cetuximab in Combination With Oxaliplatin, Capecitabine, and Radiation Therapy Followed by Surgery for Locally-advanced Rectal Cancer Not Recruiting

    1. To determine the MTD and DLTs of oxaliplatin and capecitabine when combined with C225 and radiotherapy (Phase I) 2. To determine the pathologic response rate of C225 in combination with this neoadjuvant cytotoxic regimen (Phase II)

    Stanford is currently not accepting patients for this trial. For more information, please contact Heidi Kaiser, (650) 724 - 0079.

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  • Assessment of Health Related Quality of Life in Patients Treated for Rectal Cancer Not Recruiting

    Treatment of rectal cancer often consists of surgical resection of the tumor. Chemotherapy and/or radiotherapy are frequently given before or after surgery. In this study, we wish to learn if there are differences in the treatment effectiveness or in the quality of life of patients based on their type of treatment (e.g. Radiotherapy and chemotherapy before or after surgery). Information from this questionnaire collected from you and other patients may help improve the quality of life of rectal cancer patients in the future. Medical information on your tumor, treatment received, and side effects will be compiled and maintained in a database to learn more about outcomes of treatment for rectal cancer.

    Stanford is currently not accepting patients for this trial. For more information, please contact Moe Jalali, (650) 724 - 4023.

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  • Perfusion CT as a Predictor of Treatment Response in Patients With Rectal Cancer Recruiting

    Recent advances in computed tomography (CT) technology have made CT perfusion imaging feasible for the assessment of tumor perfusion in solid tumors of the abdomen. CT perfusion has shown promising results in serving as a noninvasive method of predicting response to therapy in cancer patients. CT perfusion parameters have also been found to correlate with immunohistologic markers of angiogenesis in a number of solid tumors, suggesting a possible role for CT perfusion as a noninvasive biomarker of tumor angiogenesis. The goals of the investigators study are twofold: first, to determine the relationship between baseline CT perfusion characteristics of rectal cancers and their response to treatment, and second, to determine if perfusion CT can be used to subsequently monitor tumor response to treatment. The investigators hope to enroll those patients with locally advanced rectal cancer undergoing standard CT for pre-treatment planning, integrating CT perfusion imaging into the current abdomen/pelvis imaging protocol with close clinical and radiologic follow-up after treatment to determine response to therapy and time to disease progression.

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  • Paclitaxel, Cisplatin, and Radiation Therapy With or Without Cetuximab in Treating Patients With Locally Advanced Esophageal Cancer Not Recruiting

    RATIONALE: Drugs used in chemotherapy, such as paclitaxel and cisplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Monoclonal antibodies, such as cetuximab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Cetuximab may stop the growth of esophageal cancer by blocking blood flow to the tumor. It is not yet known whether giving paclitaxel and cisplatin together with radiation therapy is more effective with or without cetuximab in treating esophageal cancer. PURPOSE: This randomized phase III trial is comparing how well giving paclitaxel and cisplatin together with radiation therapy works with or without cetuximab in treating patients with locally advanced esophageal cancer.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laura Gable, (650) 736 - 0798.

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  • Evaluation of Stereotactic Radiosurgery For Liver Malignancies Not Recruiting

    This study is intended to establish the practicality of treating cancer in the liver with precisely administered single fractions of high-energy radiation using a radiosurgical (cross-firing) technique. A second purpose is to establish a safe dose for such therapy. Finally, the efficacy of radiosurgical ablation of liver tumors, in terms of radiographic response, will be measured.

    Stanford is currently not accepting patients for this trial. For more information, please contact Jeff Kim, (650) 498 - 7703.

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  • The Role of FDG PET in Radiation Treatment Planning for Head and Neck Cancers Not Recruiting

    In patients with cancer of the head and neck and rectum, knowing the exact location of the tumor is important for designing the radiation field to ensure delivery of high dose of radiation to the tumor while sparing surrounding normal tissues. A new medical imaging method which is a combination of positron emission tomography (PET) and computed tomography (CT) scan, has shown promise in helping the radiation oncologist in defining the exact location and extent of the tumor in certain cancers such as lung cancers. Therefore the purpose of this study is to determine if these imaging methods can be used in combination with the standard radiation treatment planning procedure to improve the accuracy to targeting your tumor with radiation. In addition the PET-CT scan, similar to the PET scan alone with better resolution, can be used to determine whether the tumor has spread to any part of the body outside of the head and neck sites.

    Stanford is currently not accepting patients for this trial. For more information, please contact Quynh-Thu Le, (650) 498 - 6184.

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  • Cyberknife Radiosurgery for Locally Advanced Pancreatic Cancer Not Recruiting

    The purpose of the trial is to test the efficacy of combining conventional chemoradiotherapy with radiosurgery for locally advanced pancreas cancer.

    Stanford is currently not accepting patients for this trial. For more information, please contact Stanford Cancer Clinical Trials Office, (650) 498 - 7061.

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  • Perfusion CT as a Predictor of Treatment Response in Patients With Hepatic Malignancies Recruiting

    The purpose of this study is to determine whether baseline CT perfusion characteristics (measurements of blood-flow using CT) of hepatic cancers can predict tumor response to treatment and whether perfusion CT after treatment can be used as a biomarker for response to treatment. Treatment may consist of chemotherapy or stereotactic body radiotherapy (SBRT)or embolization therapy.

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  • A Phase 1 Study of Safety and Bioactivity With FG-3019 in Combination With Gemcitabine and Erlotinib for Subjects With Locally Advanced or Metastatic Pancreatic Cancer Not Recruiting

    Objectives - Primary: To evaluate the safety and tolerability of FG-3019 in combination with gemcitabine and erlotinib - Secondary: To evaluate the efficacy and pharmacokinetics of FG-3019 in combination with gemcitabine and erlotinib

    Stanford is currently not accepting patients for this trial. For more information, please contact Donna Williams, (650) 498 - 6608.

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Teaching

2013-14 Courses


Postdoctoral Advisees


Graduate and Fellowship Programs


Publications

Journal Articles


  • Cost-effectiveness of modern radiotherapy techniques in locally advanced pancreatic cancer CANCER Murphy, J. D., Chang, D. T., Abelson, J., Daly, M. E., Yeung, H. N., Nelson, L. M., Koong, A. C. 2012; 118 (4): 1119-1129

    Abstract

    Radiotherapy may improve the outcome of patients with pancreatic cancer but at an increased cost. In this study, the authors evaluated the cost-effectiveness of modern radiotherapy techniques in the treatment of locally advanced pancreatic cancer.A Markov decision-analytic model was constructed to compare the cost-effectiveness of 4 treatment regimens: gemcitabine alone, gemcitabine plus conventional radiotherapy, gemcitabine plus intensity-modulated radiotherapy (IMRT); and gemcitabine with stereotactic body radiotherapy (SBRT). Patients transitioned between the following 5 health states: stable disease, local progression, distant failure, local and distant failure, and death. Health utility tolls were assessed for radiotherapy and chemotherapy treatments and for radiation toxicity.SBRT increased life expectancy by 0.20 quality-adjusted life years (QALY) at an increased cost of $13,700 compared with gemcitabine alone (incremental cost-effectiveness ratio [ICER] = $69,500 per QALY). SBRT was more effective and less costly than conventional radiotherapy and IMRT. An analysis that excluded SBRT demonstrated that conventional radiotherapy had an ICER of $126,800 per QALY compared with gemcitabine alone, and IMRT had an ICER of $1,584,100 per QALY compared with conventional radiotherapy. A probabilistic sensitivity analysis demonstrated that the probability of cost-effectiveness at a willingness to pay of $50,000 per QALY was 78% for gemcitabine alone, 21% for SBRT, 1.4% for conventional radiotherapy, and 0.01% for IMRT. At a willingness to pay of $200,000 per QALY, the probability of cost-effectiveness was 73% for SBRT, 20% for conventional radiotherapy, 7% for gemcitabine alone, and 0.7% for IMRT.The current results indicated that IMRT in locally advanced pancreatic cancer exceeds what society considers cost-effective. In contrast, combining gemcitabine with SBRT increased clinical effectiveness beyond that of gemcitabine alone at a cost potentially acceptable by today's standards.

    View details for DOI 10.1002/cncr.26365

    View details for Web of Science ID 000299834300031

    View details for PubMedID 21773972

  • Identification of an Ire1alpha endonuclease specific inhibitor with cytotoxic activity against human multiple myeloma BLOOD Papandreou, I., Denko, N. C., Olson, M., Van Melckebeke, H., Lust, S., Tam, A., Solow-Cordero, D. E., Bouley, D. M., Offner, F., Niwa, M., Koong, A. C. 2011; 117 (4): 1311-1314

    Abstract

    Activation of the adaptive Ire1-XBP1 pathway has been identified in many solid tumors and hematologic malignancies, including multiple myeloma (MM). Here, we report the identification of STF-083010, a novel small-molecule inhibitor of Ire1. STF-083010 inhibited Ire1 endonuclease activity, without affecting its kinase activity, after endoplasmic reticulum stress both in vitro and in vivo. Treatment with STF-083010 showed significant antimyeloma activity in model human MM xenografts. Similarly, STF-083010 was preferentially toxic to freshly isolated human CD138(+) MM cells compared with other similarly isolated cell populations. The identification of this novel Ire1 inhibitor supports the hypothesis that the Ire1-XBP1 axis is a promising target for anticancer therapy, especially in the context of MM.

    View details for DOI 10.1182/blood-2010-08-303099

    View details for Web of Science ID 000286623400029

    View details for PubMedID 21081713

  • Imaging the Unfolded Protein Response in Primary Tumors Reveals Microenvironments with Metabolic Variations that Predict Tumor Growth CANCER RESEARCH Spiotto, M. T., Banh, A., Papandreou, I., Cao, H., Galvez, M. G., Gurtner, G. C., Denko, N. C., Le, Q. T., Koong, A. C. 2010; 70 (1): 78-88

    Abstract

    Cancer cells exist in harsh microenvironments that are governed by various factors, including hypoxia and nutrient deprivation. These microenvironmental stressors activate signaling pathways that affect cancer cell survival. While others have previously measured microenvironmental stressors in tumors, it remains difficult to detect the real-time activation of these downstream signaling pathways in primary tumors. In this study, we developed transgenic mice expressing an X-box binding protein 1 (XBP1)-luciferase construct that served as a reporter for endoplasmic reticulum (ER) stress and as a downstream response for the tumor microenvironment. Primary mammary tumors arising in these mice exhibited luciferase activity in vivo. Multiple tumors arising in the same mouse had distinct XBP1-luciferase signatures, reflecting either higher or lower levels of ER stress. Furthermore, variations in ER stress reflected metabolic and hypoxic differences between tumors. Finally, XBP1-luciferase activity correlated with tumor growth rates. Visualizing distinct signaling pathways in primary tumors reveals unique tumor microenvironments with distinct metabolic signatures that can predict for tumor growth.

    View details for DOI 10.1158/0008-5472.CAN-09-2747

    View details for Web of Science ID 000278404300011

    View details for PubMedID 20028872

  • X box-binding protein 1 regulates angiogenesis in human pancreatic adenocarcinomas. Translational oncology Romero-Ramirez, L., Cao, H., Regalado, M. P., Kambham, N., Siemann, D., Kim, J. J., Le, Q. T., Koong, A. C. 2009; 2 (1): 31-38

    Abstract

    Tumors encounter endoplasmic reticulum stress during tumor growth and activate an adaptive pathway known as the unfolded protein response (UPR). Because this pathway is induced by the tumor microenvironment, it is a promising target for cancer therapy. We have previously demonstrated that X-box binding protein 1 (XBP-1), a key regulator of the UPR, was required for survival under hypoxia and critical for tumor growth in tumor xenografts. In this study, we investigated the role of XBP-1 in regulating tumor angiogenesis.We used an intradermal angiogenesis model to quantify the effect of XBP-1 on angiogenesis. We also used a human tumor xenograft model to assay for tumor growth delay. We determined vascular endothelial growth factor (VEGF) expression by quantitative polymerase chain reaction and ELISA. Finally, we stained human pancreatic adenocarcinoma specimens for XBP-1 expression and correlated the expression pattern of XBP-1 with CD31 (endothelial cell marker) expression.We demonstrated that XBP-1 is essential for angiogenesis during early tumor growth. Inhibiting XBP-1 expression by short-hairpin RNA sequence specific for XBP-1 reduced blood vessel formation in tumors from mouse embryonic fibroblast cells and human fibrosarcoma tumor cells (HT1080). Expressing a dominant-negative form of IRE1alpha also reduced blood vessel formation in tumors. Moreover, expression of spliced XBP-1 (XBP-1s) restored angiogenesis in IRE1alpha dominant-negative expressing cells. We further demonstrated that XBP-1-mediated angiogenesis does not depend on VEGF.We propose that the IRE1alpha-XBP-1 branch of the UPR modulates a complex proangiogenic, VEGF-independent response that depends on signals received from the tumor microenvironment.

    View details for PubMedID 19252749

  • Stereotactic Radiotherapy for Unresectable Adenocarcinoma of the Pancreas CANCER Chang, D. T., Schellenberg, D., Shen, J., Kim, J., Goodman, K. A., Fisher, G. A., Ford, J. M., Desser, T., Quon, A., Koong, A. C. 2009; 115 (3): 665-672

    Abstract

    The authors report on the local control and toxicity of stereotactic body radiotherapy (SBRT) for patients with unresectable pancreatic adenocarcinoma.Seventy-seven patients with unresectable adenocarcinoma of the pancreas received 25 gray (Gy) in 1 fraction. Forty-five patients (58%) had locally advanced disease, 11 patients (14%) had medically inoperable disease, 15 patients (19%) had metastatic disease, and 6 patients (8%) had locally recurrent disease. Nine patients (12%) had received prior chemoradiotherapy. Sixteen patients (21%) received between 45 to 54 Gy of fractionated radiotherapy and SBRT. Various gemcitabine-based chemotherapy regimens were received by 74 patients (96%), but 3 patients (4%) did not receive chemotherapy until they had distant failure.The median follow-up was 6 months (range, 3-31 months) and, among surviving patients, it was 12 months (range, 3-31 months). The overall rates of freedom from local progression (FFLP) at 6 months and 12 months were 91% and 84%, respectively. The 6- and 12-month isolated local recurrence rates were 5% and 5%, respectively. There was no difference in the 12-month FFLP rate based on tumor location (head/uncinate, 91% vs body/tail, 86%; P = .52). The progression-free survival (PFS) rates at 6 months and 12 months were 26% and 9%, respectively. The PFS rate at 6 months was superior for patients who had nonmetastatic disease versus patients who had metastatic disease (28% vs 15%; P = .05). The overall survival (OS) rates at 6 months and 12 months from SBRT were 56% and 21%, respectively. Four patients (5%) experienced grade > or = 2 acute toxicity. Three patients (4%) experienced grade 2 late toxicity, and 7 patients (9%) experienced grade > or = 3 late toxicity. At 6 months and 12 months, the rates of grade > or = 2 late toxicity were 11% and 25%, respectively.SBRT for pancreatic adenocarcinoma was effective for local control with associated risk of toxicity and should be used with rigorous attention to quality assurance. Efforts to reduce complications are warranted. Distant metastases account for the vast majority of disease-related mortality.

    View details for DOI 10.1002/cncr.24059

    View details for Web of Science ID 000263003400025

    View details for PubMedID 19117351

  • The Role of Tumor Cell-Derived Connective Tissue Growth Factor (CTGF/CCN2) in Pancreatic Tumor Growth CANCER RESEARCH Bennewith, K. L., Huang, X., Ham, C. M., Graves, E. E., Erler, J. T., Kambham, N., Feazell, J., Yang, G. P., Koong, A., Giaccia, A. J. 2009; 69 (3): 775-784

    Abstract

    Pancreatic cancer is highly aggressive and refractory to existing therapies. Connective tissue growth factor (CTGF/CCN2) is a fibrosis-related gene that is thought to play a role in pancreatic tumor progression. However, CCN2 can be expressed in a variety of cell types, and the contribution of CCN2 derived from either tumor cells or stromal cells as it affects the growth of pancreatic tumors is unknown. Using genetic inhibition of CCN2, we have discovered that CCN2 derived from tumor cells is a critical regulator of pancreatic tumor growth. Pancreatic tumor cells derived from CCN2 shRNA-expressing clones showed dramatically reduced growth in soft agar and when implanted s.c. We also observed a role for CCN2 in the growth of pancreatic tumors implanted orthotopically, with tumor volume measurements obtained by positron emission tomography imaging. Mechanistically, CCN2 protects cells from hypoxia-mediated apoptosis, providing an in vivo selection for tumor cells that express high levels of CCN2. We found that CCN2 expression and secretion was increased in hypoxic pancreatic tumor cells in vitro, and we observed colocalization of CCN2 and hypoxia in pancreatic tumor xenografts and clinical pancreatic adenocarcinomas. Furthermore, we found increased CCN2 staining in clinical pancreatic tumor tissue relative to stromal cells surrounding the tumor, supporting our assertion that tumor cell-derived CCN2 is important for pancreatic tumor growth. Taken together, these data improve our understanding of the mechanisms responsible for pancreatic tumor growth and progression, and also indicate that CCN2 produced by tumor cells represents a viable therapeutic target for the treatment of pancreatic cancer.

    View details for DOI 10.1158/0008-5472.CAN-08-0987

    View details for Web of Science ID 000263048700010

    View details for PubMedID 19179545

  • Hypoxia-Induced Lysyl Oxidase Is a Critical Mediator of Bone Marrow Cell Recruitment to Form the Premetastatic Niche CANCER CELL Erler, J. T., Bennewith, K. L., Cox, T. R., Lang, G., Bird, D., Koong, A., Le, Q., Giaccia, A. J. 2009; 15 (1): 35-44

    Abstract

    Tumor cell metastasis is facilitated by "premetastatic niches" formed in destination organs by invading bone marrow-derived cells (BMDCs). Lysyl oxidase (LOX) is critical for premetastatic niche formation. LOX secreted by hypoxic breast tumor cells accumulates at premetastatic sites, crosslinks collagen IV in the basement membrane, and is essential for CD11b+ myeloid cell recruitment. CD11b+ cells adhere to crosslinked collagen IV and produce matrix metalloproteinase-2, which cleaves collagen, enhancing the invasion and recruitment of BMDCs and metastasizing tumor cells. LOX inhibition prevents CD11b+ cell recruitment and metastatic growth. CD11b+ cells and LOX also colocalize in biopsies of human metastases. Our findings demonstrate a critical role for LOX in premetastatic niche formation and support targeting LOX for the treatment and prevention of metastatic disease.

    View details for DOI 10.1016/j.ccr.2008.11.012

    View details for Web of Science ID 000262334800007

    View details for PubMedID 19111879

  • Multiplexed protein detection by proximity ligation for cancer biomarker validation NATURE METHODS Fredriksson, S., Dixon, W., Ji, H., Koong, A. C., Mindrinos, M., Davis, R. W. 2007; 4 (4): 327-329

    Abstract

    We present a proximity ligation-based multiplexed protein detection procedure in which several selected proteins can be detected via unique nucleic-acid identifiers and subsequently quantified by real-time PCR. The assay requires a 1-microl sample, has low-femtomolar sensitivity as well as five-log linear range and allows for modular multiplexing without cross-reactivity. The procedure can use a single polyclonal antibody batch for each target protein, simplifying affinity-reagent creation for new biomarker candidates.

    View details for DOI 10.1038/NMETH1020

    View details for Web of Science ID 000245584900013

    View details for PubMedID 17369836

  • Connective tissue growth factor-specific monoclonal antibody therapy inhibits pancreatic tumor growth and metastasis CANCER RESEARCH Dornhoefer, N., Spong, S., Bennewith, K., Salim, A., Klaus, S., Kambham, N., Wong, C., Kaper, F., Sutphin, P., Nacalumi, R., Hoeckel, M., Le, Q., Longaker, M., Yang, G., Koong, A., Giaccia, A. 2006; 66 (11): 5816-5827

    Abstract

    Pancreatic cancer is highly aggressive and refractory to most existing therapies. Past studies have shown that connective tissue growth factor (CTGF) expression is elevated in human pancreatic adenocarcinomas and some pancreatic cancer cell lines. To address whether and how CTGF influences tumor growth, we generated pancreatic tumor cell lines that overexpress different levels of human CTGF. The effect of CTGF overexpression on cell proliferation was measured in vitro in monolayer culture, suspension culture, or soft agar, and in vivo in tumor xenografts. Although there was no effect of CTGF expression on proliferation in two-dimensional cultures, anchorage-independent growth (AIG) was enhanced. The capacity of CTGF to enhance AIG in vitro was linked to enhanced pancreatic tumor growth in vivo when these cells were implanted s.c. in nude mice. Administration of a neutralizing CTGF-specific monoclonal antibody, FG-3019, had no effect on monolayer cell proliferation, but blocked AIG in soft agar. Consistent with this observation, anti-CTGF treatment of mice bearing established CTGF-expressing tumors abrogated CTGF-dependent tumor growth and inhibited lymph node metastases without any toxicity observed in normal tissue. Together, these studies implicate CTGF as a new target in pancreatic cancer and suggest that inhibition of CTGF with a human monoclonal antibody may control primary and metastatic tumor growth.

    View details for DOI 10.1158/0008-5472.CAN-06-0081

    View details for Web of Science ID 000238003100038

    View details for PubMedID 16740721

  • Galectin-1: A link between tumor hypoxia and tumor immune privilege JOURNAL OF CLINICAL ONCOLOGY Le, Q. T., Shi, G. Y., Cao, H. B., Nelson, D. W., Wang, Y. Y., CHEN, E. Y., Zhao, S. C., Kong, C., Richardson, D., O'Byrne, K. J., Giaccia, A. J., Koong, A. C. 2005; 23 (35): 8932-8941

    Abstract

    To identify a 15-KDa novel hypoxia-induced secreted protein in head and neck squamous cell carcinomas (HNSCC) and to determine its role in malignant progression.We used surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS) and tandem MS to identify a novel hypoxia-induced secreted protein in FaDu cells. We used immunoblots, real-time polymerase chain reaction (PCR), and enzyme-linked immunoabsorbent assay to confirm the hypoxic induction of this secreted protein as galectin-1 in cell lines and xenografts. We stained tumor tissues from 101 HNSCC patients for galectin-1, CA IX (carbonic anhydrase IX, a hypoxia marker) and CD3 (a T-cell marker). Expression of these markers was correlated to each other and to treatment outcomes.SELDI-TOF studies yielded a hypoxia-induced peak at 15 kDa that proved to be galectin-1 by MS analysis. Immunoblots and PCR studies confirmed increased galectin-1 expression by hypoxia in several cancer cell lines. Plasma levels of galectin-1 were higher in tumor-bearing severe combined immunodeficiency (SCID) mice breathing 10% O2 compared with mice breathing room air. In HNSCC patients, there was a significant correlation between galectin-1 and CA IX staining (P = .01) and a strong inverse correlation between galectin-1 and CD3 staining (P = .01). Expression of galectin-1 and CD3 were significant predictors for overall survival on multivariate analysis.Galectin-1 is a novel hypoxia-regulated protein and a prognostic marker in HNSCC. This study presents a new mechanism on how hypoxia can affect the malignant progression and therapeutic response of solid tumors by regulating the secretion of proteins that modulate immune privilege.

    View details for DOI 10.1200/JCO.2005.02.0206

    View details for Web of Science ID 000234026500004

    View details for PubMedID 16219933

  • The unfolded protein response: A novel component of the hypoxic stress response in tumors MOLECULAR CANCER RESEARCH Feldman, D. E., Chauhan, V., Koong, A. C. 2005; 3 (11): 597-605

    Abstract

    Hypoxia is a physiologically important endoplasmic reticulum (ER) stress that is present in all solid tumors. Numerous clinical studies have shown that tumor hypoxia predicts for decreased local control, increased distant metastases, and decreased overall survival in a variety of human tumors. Hypoxia selects for tumors with an increased malignant phenotype and increases the metastatic potential of tumor cells. Tumor cells respond to hypoxia and ER stress through the activation of the unfolded protein response (UPR). The UPR is an adaptive response to increase cell survival during ER stress. XBP-1 is a critical transcriptional regulator of this process and is required for tumor growth. Pancreatic ER kinase (PKR-like ER kinase) regulates the translational branch of the UPR and is also important in the growth of tumors. Although the exact mechanism has yet to be elucidated, recent data suggest that the UPR affects tumor growth through protection from apoptosis and may influence angiogenic signaling pathways. Targeting various components of the UPR is a promising therapeutic strategy. Understanding the relationship between hypoxia, the UPR, and tumor growth is crucial to improving current cancer therapies.

    View details for DOI 10.1158/1541-7786.MCR-05-0221

    View details for Web of Science ID 000233959900001

    View details for PubMedID 16317085

  • Identification of hypoxia-regulated proteins in head and neck cancer by proteomic and tissue array profiling CANCER RESEARCH Chen, Y. J., Shi, G. Y., Wei, X., Kong, C., Zhao, S. C., Gaw, A. F., CHEN, E. Y., Yang, G. P., Giaccia, A. J., Le, Q. T., Koong, A. C. 2004; 64 (20): 7302-7310

    Abstract

    Hypoxia within solid tumors decreases therapeutic efficacy, and identification of hypoxia markers may influence the choice of therapeutic modality. Here, we used a proteomic approach to identify hypoxia-regulated proteins and validated their use as endogenous indicators of tumor hypoxia. Using two-dimensional gel electrophoresis and PowerBlot (antibody-based array), we identified a group of 20 proteins that are increased >/=1.5-fold during hypoxia. The majority of these proteins such as IkappaB kinase beta (IKKbeta), MKK3b, highly expressed in cancer (HEC), density-regulated protein 1, P150(glued), nuclear transport factor 2, binder of ARL 2, Paxillin, and transcription termination factor I have not been previously reported to be hypoxia inducible. The increase in these proteins under hypoxia was mediated through posttranscriptional mechanisms. We additionally characterized the role of IKKbeta, a regulator of the nuclear factor-kappaB transcription factor, during hypoxia. We demonstrated that IKKbeta mediates cell survival during hypoxia and is induced in a variety of squamous cell carcinoma cell lines. Furthermore, we showed that IKKbeta expression from tumor specimens correlated with tumor oxygenation in patients with head and neck squamous cell carcinomas. These data suggest that IKKbeta is a novel endogenous marker of tumor hypoxia and may represent a new target for anticancer therapy.

    View details for Web of Science ID 000224522200021

    View details for PubMedID 15492250

  • XBP1 is essential for survival under hypoxic conditions and is required for tumor growth CANCER RESEARCH Romero-Ramirez, L., Cao, H. B., Nelson, D., Hammond, E., Lee, A. H., Yoshida, H., Mori, K., Glimcher, L. H., Denko, N. C., Giaccia, A. J., Le, Q. T., Koong, A. C. 2004; 64 (17): 5943-5947

    Abstract

    Hypoxia within solid tumors is a major determinant of outcome after anticancer therapy. Analysis of gene expression changes during hypoxia indicated that unfolded protein response genes were one of the most robustly induced groups of genes. In this study, we investigated the hypoxic regulation of X-box binding protein (XBP1), a major transcriptional regulator of the unfolded protein response. Hypoxia induced XBP1 at the transcriptional level and activated splicing of its mRNA, resulting in increased levels of activated XBP1 protein. After exposure to hypoxia, apoptosis increased and clonogenic survival decreased in XBP1-deficient cells. Loss of XBP1 severely inhibited tumor growth due to a reduced capacity for these transplanted tumor cells to survive in a hypoxic microenvironment. Taken together, these studies directly implicate XBP1 as an essential survival factor for hypoxic stress and tumor growth.

    View details for Web of Science ID 000223603200007

    View details for PubMedID 15342372

  • Phase I study of stereotactic radiosurgery in patients with locally advanced pancreatic cancer INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Koong, A. C., Le, Q. T., Ho, A., Fong, B., Fisher, G., Cho, C., Ford, J., Poen, J., Gibbs, I. C., Mehta, V. K., Kee, S., Trueblood, W., Yang, G., Bastidas, J. A. 2004; 58 (4): 1017-1021

    Abstract

    To determine the feasibility and toxicity of delivering stereotactic radiosurgery to patients with locally advanced pancreatic cancer.Patients with Eastern Cooperative Oncology Group performance status < or=2 and locally advanced pancreatic cancer were enrolled on this Phase I dose escalation study. Patients received a single fraction of radiosurgery consisting of either 15 Gy, 20 Gy, or 25 Gy to the primary tumor. Acute gastrointestinal toxicity was scored according to the Radiation Therapy Oncology Group criteria. Response to treatment was determined by serial high-resolution computed tomography scanning.Fifteen patients were treated at 3 dose levels (3 patients received 15 Gy, 5 patients received 20 Gy, and 7 patients received 25 Gy). At these doses, no Grade 3 or higher acute gastrointestinal toxicity was observed. This trial was stopped before any dose-limiting toxicity was reached, because the clinical objective of local control was achieved in all 6 evaluable patients treated at 25 Gy.It is feasible to deliver stereotactic radiosurgery to patients with locally advanced pancreatic cancer. The recommended dose to achieve local control without significant acute gastrointestinal toxicity is 25 Gy.

    View details for DOI 10.1016/j.ijrobp.2003.11.004

    View details for Web of Science ID 000220084200001

    View details for PubMedID 15001240

  • Loss of PTEN facilitates HIF-1-mediated gene expression GENES & DEVELOPMENT Zundel, W., Schindler, C., Haas-Kogan, D., Koong, A., Kaper, F., Chen, E., Gottschalk, A. R., Ryan, H. E., Johnson, R. S., Jefferson, A. B., Stokoe, D., Giaccia, A. J. 2000; 14 (4): 391-396

    Abstract

    In glioblastoma-derived cell lines, PTEN does not significantly alter apoptotic sensitivity or cause complete inhibition of DNA synthesis. However, in these cell lines PTEN regulates hypoxia- and IGF-1-induced angiogenic gene expression by regulating Akt activation of HIF-1 activity. Restoration of wild-type PTEN to glioblastoma cell lines lacking functional PTEN ablates hypoxia and IGF-1 induction of HIF-1-regulated genes. In addition, Akt activation leads to HIF-1alpha stabilization, whereas PTEN attenuates hypoxia-mediated HIF-1alpha stabilization. We propose that loss of PTEN during malignant progression contributes to tumor expansion through the deregulation of Akt activity and HIF-1-regulated gene expression.

    View details for Web of Science ID 000085571300001

    View details for PubMedID 10691731

  • Candidate genes for the hypoxic tumor phenotype CANCER RESEARCH Koong, A. C., Denko, N. C., Hudson, K. M., Schindler, C., Swiersz, L., Koch, C., Evans, S., Ibrahim, H., Le, Q. T., Terris, D. J., Giaccia, A. J. 2000; 60 (4): 883-887

    Abstract

    In this study, we have analyzed changes induced by hypoxia at the transcriptional level of genes that could be responsible for a more aggressive phenotype. Using a series of DNA array membranes, we identified a group of hypoxia-induced genes that included plasminogen activator inhibitor-1 (PAI-1), insulin-like growth factor-binding protein 3 (IGFBP-3), endothelin-2, low-density lipoprotein receptor-related protein (LRP), BCL2-interacting killer (BIK), migration-inhibitory factor (MIF), matrix metalloproteinase-13 (MMP-13), fibroblast growth factor-3 (FGF-3), GADD45, and vascular endothelial growth factor (VEGF). The induction of each gene was confirmed by Northern blot analysis in two different squamous cell carcinoma-derived cell lines. We also analyzed the kinetics of PAI-1 induction by hypoxia in more detail because it is a secreted protein that may serve as a useful molecular marker of hypoxia. On exposure to hypoxia, there was a gradual increase in PAI-1 mRNA between 2 and 24 h of hypoxia followed by a rapid decay after 2 h of reoxygenation. PAI-1 levels were also measured in the serum of a small group of head and neck cancer patients and were found to correlate with the degree of tumor hypoxia found in these patients.

    View details for Web of Science ID 000085503100022

    View details for PubMedID 10706099

  • Intrafraction Verification of Gated RapidArc by Using Beam-Level Kilovoltage X-Ray Images INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Li, R., Mok, E., Chang, D. T., Daly, M., Loo, B. W., Diehn, M., Quynh-Thu Le, Q. T., Koong, A., Xing, L. 2012; 83 (5): E709-E715

    Abstract

    To verify the geometric accuracy of gated RapidArc treatment using kV images acquired during dose delivery.Twenty patients were treated using the gated RapidArc technique with a Varian TrueBeam STx linear accelerator. One to 7 metallic fiducial markers were implanted inside or near the tumor target before treatment simulation. For patient setup and treatment verification purposes, the internal target volume (ITV) was created, corresponding to each implanted marker. The gating signal was generated from the Real-time Position Management (RPM) system. At the beginning of each fraction, individualized respiratory gating amplitude thresholds were set based on fluoroscopic image guidance. During the treatment, we acquired kV images immediately before MV beam-on at every breathing cycle, using the on-board imaging system. After the treatment, all implanted markers were detected, and their 3-dimensional (3D) positions in the patient were estimated using software developed in-house. The distance from the marker to the corresponding ITV was calculated for each patient by averaging over all markers and all fractions.The average 3D distance between the markers and their ITVs was 0.8 ± 0.5 mm (range, 0-1.7 mm) and was 2.1 ± 1.2 mm at the 95th percentile (range, 0-3.8 mm). On average, a left-right margin of 0.6 mm, an anterior-posterior margin of 0.8 mm, and a superior-inferior margin of 1.5 mm is required to account for 95% of the intrafraction uncertainty in RPM-based RapidArc gating.To our knowledge, this is the first clinical report of intrafraction verification of respiration-gated RapidArc treatment in stereotactic ablative radiation therapy. For some patients, the markers deviated significantly from the ITV by more than 2 mm at the beginning of the MV beam-on. This emphasizes the need for gating techniques with beam-on/-off controlled directly by the actual position of the tumor target instead of external surrogates such as RPM.

    View details for DOI 10.1016/j.ijrobp.2012.03.006

    View details for Web of Science ID 000306128100022

    View details for PubMedID 22554582

  • Clinicopathologic and molecular features of sporadic early-onset colorectal adenocarcinoma: an adenocarcinoma with frequent signet ring cell differentiation, rectal and sigmoid involvement, and adverse morphologic features MODERN PATHOLOGY Chang, D. T., Pai, R. K., Rybicki, L. A., DiMaio, M. A., Limaye, M., Jayachandran, P., Koong, A. C., Kunz, P. A., Fisher, G. A., Ford, J. M., Welton, M., Shelton, A., Ma, L., Arber, D. A., Pai, R. K. 2012; 25 (8): 1128-1139

    Abstract

    Recent literature suggests an increasing incidence of colorectal carcinoma in young patients. We performed a histologic, molecular, and immunophenotypic analysis of patients with sporadic early-onset (?40 years of age) colorectal carcinoma seen at our institution from the years 2000-2010 and compared these tumors to a cohort of consecutively resected colorectal carcinomas seen in patients >40 years of age. A total of 1160 primary colorectal adenocarcinomas were surgically resected for the years 2000 through 2010. Of these, 75 (6%) were diagnoses in patients ?40 years of age of which 13 (17%) demonstrated abnormalities in DNA mismatch repair, 4 (5%) were in patients with known germline genetic disorders (two patients with familial adenomatous polyposis, one patient with juvenile polyposis, and one patient with Li-Fraumeni syndrome), and three patients (4%) had long-standing chronic inflammatory bowel disease. The sporadic early-onset colorectal carcinoma group comprised a total of 55 patients (55/1160, 5%) and were compared with a control group comprising 73 consecutively resected colorectal carcinomas with proficient DNA mismatch repair in patients >40 years of age. For the early-onset colorectal carcinoma group, most cases (33/55, 60%) were diagnosed between the age of 35 and 40 years of age. Compared with the control group, the early-onset colorectal carcinoma group was significantly different with respect to tumor location (P<0.007) with 80% (44/55 cases) identified in either the sigmoid colon (24/55, 44%) or rectum (20/55, 36%). Morphologically, early-onset colorectal carcinomas more frequently displayed adverse histologic features compared with the control colorectal carcinoma group such as signet ring cell differentiation (7/55, 13% vs 1/73, 1%, P=0.021), perineural invasion (16/55, 29% vs 8/73, 11%, P=0.009) and venous invasion (12/55, 22% vs 4/73, 6%, P=0.006). A precursor adenomatous lesion was less frequently identified in the early-onset colorectal carcinoma group compared with the control group (19/55, 35% vs 39/73, 53%, P=0.034). Of the early-onset colorectal carcinomas, only 2/45 cases (4%) demonstrated KRAS mutations compared with 11/73 (15%) of the control group colorectal adenocarcinomas harboring KRAS mutations, although this difference did not reach statistical significance (P=0.13). BRAF V600E mutations were not identified in the early-onset colorectal carcinoma group. No difference was identified between the two groups with regard to tumor stage, tumor size, number of lymph node metastases, lymphatic invasion, tumor budding, mucinous histology, or tumor-infiltrating lymphocytes. Both groups had similar recurrence-free (P=0.28) and overall survival (P=0.73). However, patients in the early-onset colorectal carcinoma group more frequently either presented with or developed metastatic disease during their disease course compared with the control colorectal carcinoma group (25/55, 45% vs 18/73, 25%, P=0.014). In addition, 8/55 patients (15%) in the early-onset colorectal carcinoma group developed local recurrence of their tumor while no patients in the control colorectal carcinoma group developed local recurrence (P<0.001), likely due to the increased incidence of rectal carcinoma in the patients with early-onset colorectal carcinoma. Our study demonstrates that colorectal carcinoma is not infrequently diagnosed in patients ?40 years of age and is not frequently the result of underlying Lynch syndrome or associated with other cancer-predisposing genetic conditions or chronic inflammatory conditions. These tumors have a striking predilection for the distal colon, particularly the sigmoid colon and rectum and are much more likely to demonstrate adverse histologic factors, including signet ring cell differentiation, venous invasion, and perineural invasion.

    View details for DOI 10.1038/modpathol.2012.61

    View details for Web of Science ID 000307222200008

    View details for PubMedID 22481281

  • A novel epidermal growth factor receptor variant lacking multiple domains directly activates transcription and is overexpressed in tumors ONCOGENE Piccione, E. C., LIEU, T. J., Gentile, C. F., Williams, T. R., Connolly, A. J., Godwin, A. K., Koong, A. C., Wong, A. J. 2012; 31 (24): 2953-2967

    Abstract

    The epidermal growth factor receptor (EGFR) is essential to multiple physiological and neoplastic processes via signaling by its tyrosine kinase domain and subsequent activation of transcription factors. EGFR overexpression and alteration, including point mutations and structural variants, contribute to oncogenesis in many tumor types. In this study, we identified an in-frame splice variant of the EGFR called mini-LEEK (mLEEK) that is more broadly expressed than the EGFR and is overexpressed in several cancers. Unlike previously characterized EGFR variants, mLEEK lacks the extracytoplasmic, transmembrane and tyrosine kinase domains. mLEEK localizes in the nucleus and functions as a transcription factor to regulate target genes involved in the cellular response to endoplasmic reticulum (ER) stress, including the master regulator of the unfolded protein response (UPR) pathways, molecular chaperone GRP78/Bip. We demonstrated that mLEEK regulates GRP78 transcription through direct interaction with a cis-regulatory element within the gene promoter. Several UPR pathways were interrogated and mLEEK expression was found to attenuate the induction of all pathways upon ER stress. Conversely, knockdown of mLEEK resulted in caspase-mediated cell death and sensitization to ER stress. These findings indicate that mLEEK levels determine cellular responses to unfavorable conditions that cause ER stress. This information, along with the overexpression of mLEEK in tumors, suggests unique strategies for therapeutic intervention. Furthermore, the identification of mLEEK expands the known mechanisms by which the EGFR gene contributes to oncogenesis and represents the first link between two previously disparate areas in cancer cell biology: EGFR signaling and the UPR.

    View details for DOI 10.1038/onc.2011.465

    View details for Web of Science ID 000305388400005

    View details for PubMedID 21986942

  • Orthovoltage Intraoperative Radiotherapy for Locally Advanced and Recurrent Colorectal Cancer DISEASES OF THE COLON & RECTUM Daly, M. E., Kapp, D. S., Maxim, P. G., Welton, M. L., Tran, P. T., Koong, A. C., Chang, D. T. 2012; 55 (6): 695-702

    Abstract

    Locally advanced and recurrent colorectal cancers pose a significant therapeutic challenge. Orthovoltage intraoperative radiotherapy provides one potential means of improving disease control at the time of surgery.This study sought to analyze outcomes and identify prognostic factors of patients treated with orthovoltage intraoperative radiotherapy for locally advanced or recurrent colorectal cancer.This study is a retrospective chart review conducted at a tertiary medical center.Between January 1990 and July 2009, 55 patients underwent intraoperative radiotherapy to a total of 61 sites for locally advanced (n = 14) or recurrent (n = 41) cancers of colon (n = 18) or rectum/rectosigmoid junction (n = 37).Median dose was 12 Gy (range, 7.5-20 Gy). Among locally advanced rectal/rectosigmoid cases, surgery included abdominoperineal resection (n = 3) or low anterior resection (n = 9). Seven treated sites had gross residual (R2) disease, 28 had pathologic or clinical microscopic residual disease (R1), and 15 were complete resections (R0). Treated sites included sacrum (n = 22), anterior pelvis/pelvic sidewall (19), sacrum and sidewall (n = 1), aortic bifurcation (n = 2), vaginal cuff (n = 2), psoas (n = 3), perivesicular region (n = 2), and other (n = 10).Outcomes measures included in-field local control, locoregional control, overall survival, and grade ?3 toxicity.At a median follow-up of 27 months (range, 4-237) among living patients, 2-year Kaplan-Meier estimates of in-field local control, locoregional control, and overall survival were 69%, 51%, and 59%. Margin status predicted for improved locoregional control (p = 0.01) and overall survival (p = 0.01). Seventeen patients (31%) developed a grade 3 to 5 toxicity following surgery with intraoperative radiotherapy.This study was limited by its retrospective nature and relatively small sample size.Local control with intraoperative radiotherapy for locally advanced and recurrent colorectal cancers is good despite the high risk of residual disease. Among carefully selected patients, multimodality regimens including intraoperative radiotherapy may permit long-term survival.

    View details for DOI 10.1097/DCR.0b013e31824d464c

    View details for Web of Science ID 000304368500011

    View details for PubMedID 22595850

  • Evaluation of the geometric accuracy of surrogate-based gated VMAT using intrafraction kilovoltage x-ray images MEDICAL PHYSICS Li, R., Mok, E., Han, B., Koong, A., Xing, L. 2012; 39 (5): 2686-2693

    Abstract

    To evaluate the geometric accuracy of beam targeting in external surrogate-based gated volumetric modulated arc therapy (VMAT) using kilovoltage (kV) x-ray images acquired during dose delivery.Gated VMAT treatments were delivered using a Varian TrueBeam STx Linac for both physical phantoms and patients. Multiple gold fiducial markers were implanted near the target. The reference position was created for each implanted marker, representing its correct position at the gating threshold. The gating signal was generated from the RPM system. During the treatment, kV images were acquired immediately before MV beam-on at every breathing cycle, using the on-board imaging system. All implanted markers were detected and their 3D positions were estimated using in-house developed software. The positioning error of a marker is defined as the distance of the marker from its reference position for each frame of the images. The overall error of the system is defined as the average over all markers. For the phantom study, both sinusoidal motion (1D and 3D) and real human respiratory motion was simulated for the target and surrogate. In the baseline case, the two motions were synchronized for the first treatment fraction. To assess the effects of surrogate-target correlation on the geometric accuracy, a phase shift of 5% and 10% between the two motions was introduced. For the patient study, intrafraction kV images of five stereotactic body radiotherapy (SBRT) patients were acquired for one or two fractions.For the phantom study, a high geometric accuracy was achieved in the baseline case (average error: 0.8 mm in the superior-inferior or SI direction). However, the treatment delivery is prone to geometric errors if changes in the target-surrogate relation occur during the treatment: the average error was increased to 2.3 and 4.7 mm for the phase shift of 5% and 10%, respectively. Results obtained with real human respiratory curves show a similar trend. For a target with 3D motion, the technique is able to detect geometric errors in the left-right (LR) and anterior-posterior (AP) directions. For the patient study, the average intrafraction positioning errors are 0.8, 0.9, and 1.4 mm and 95th percentile errors are 1.7, 2.1, and 2.7 mm in the LR, AP, and SI directions, respectively.The correlation between external surrogate and internal target motion is crucial to ensure the geometric accuracy of surrogate-based gating. Real-time guidance based on kV x-ray images overcomes the potential issues in surrogate-based gating and can achieve accurate beam targeting in gated VMAT.

    View details for DOI 10.1118/1.4704729

    View details for Web of Science ID 000303604300039

    View details for PubMedID 22559639

  • BRAF-mutated, Microsatellite-stable Adenocarcinoma of the Proximal Colon: An Aggressive Adenocarcinoma With Poor Survival, Mucinous Differentiation, and Adverse Morphologic Features AMERICAN JOURNAL OF SURGICAL PATHOLOGY Pai, R. K., Jayachandran, P., Koong, A. C., Chang, D. T., Kwok, S., Ma, L., Arber, D. A., Balise, R. R., Tubbs, R. R., Shadrach, B., Pai, R. K. 2012; 36 (5): 744-752

    Abstract

    The association of BRAF V600E mutation and the presence of the CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) often confound analysis of BRAF mutation status and survival in colorectal carcinoma. We evaluated a consecutive series of proximal colonic adenocarcinomas for mismatch repair protein abnormalities/MSI, BRAF V600E mutation, and KRAS mutations in an attempt to determine the prognostic significance of these abnormalities and to correlate histopathologic features with molecular alterations. Of the 259 proximal colon adenocarcinomas analyzed for mismatch repair protein abnormalities and/or MSI, 181 proximal colonic adenocarcinomas demonstrated proficient DNA mismatch repair using either MSI PCR (n=78), mismatch repair protein immunohistochemistry (n=91), or both MSI PCR and mismatch repair immunohistochemistry (n=12); these were tested for the BRAF V600E mutation and KRAS mutations. Compared with BRAF wild-type adenocarcinomas, BRAF-mutated adenocarcinomas more frequently demonstrated adverse histologic features such as lymphatic invasion (16/20, 80% vs. 75/161, 47%; P=0.008), mean number of lymph node metastases (4.5 vs. 2.2; P=0.01), perineural invasion (8/20, 40% vs. 13/161, 8%; P=0.0004), and high tumor budding (16/20, 80% vs. 83/161, 52%; P=0.02). BRAF-mutated adenocarcinomas frequently contained areas with mucinous histology (P=0.0002) and signet ring histology (P=0.03), compared with KRAS-mutated and KRAS/BRAF wild-type adenocarcinomas. Clinical follow-up data were available for 173 proximal colonic adenocarcinomas with proficient DNA mismatch repair. Patients with BRAF-mutated adenocarcinomas had a median survival of 12.3 months with a 1-year probability of survival of 54% and a 1-year disease-free survival of 56%. Patients with KRAS-mutated and KRAS/BRAF wild-type adenocarcinomas had significantly improved overall survival (unadjusted log-rank P=0.03 and unadjusted log-rank P=0.0002, respectively) and disease-free survival (unadjusted log-rank P=0.02 and unadjusted log-rank P=0.02, respectively) compared with patients with BRAF-mutated adenocarcinomas. When adjusting for tumor stage, survival analysis demonstrated that patients with BRAF-mutated adenocarcinoma had a significantly poor overall survival and disease-free survival (hazard ratios 6.63, 95% CI, 2.60-16.94; and 6.08, 95% CI, 2.11-17.56, respectively) compared with patients with KRAS/BRAF wild-type adenocarcinomas. No significant difference in overall or disease-free survival was identified between patients with KRAS-mutated and KRAS/BRAF wild-type adenocarcinomas. Our results demonstrate that BRAF-mutated proximal colon adenocarcinomas with proficient DNA mismatch repair have a dismal prognosis with an aggressive clinical course and often display mucinous differentiation, focal signet ring histology, and other adverse histologic features such as lymphatic and perineural invasion and high tumor budding.

    View details for DOI 10.1097/PAS.0b013e31824430d7

    View details for Web of Science ID 000302814000013

    View details for PubMedID 22314188

  • Quantitation of Human Papillomavirus DNA in Plasma of Oropharyngeal Carcinoma Patients INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Cao, H., Banh, A., Kwok, S., Shi, X., Wu, S., Krakow, T., Khong, B., Bavan, B., Bala, R., Pinsky, B. A., Colevas, D., Pourmand, N., Koong, A. C., Kong, C. S., Quynh-Thu Le, Q. T. 2012; 82 (3): E351-E358

    Abstract

    To determine whether human papillomavirus (HPV) DNA can be detected in the plasma of patients with HPV-positive oropharyngeal carcinoma (OPC) and to monitor its temporal change during radiotherapy.We used polymerase chain reaction to detect HPV DNA in the culture media of HPV-positive SCC90 and VU147T cells and the plasma of SCC90 and HeLa tumor-bearing mice, non-tumor-bearing controls, and those with HPV-negative tumors. We used real-time quantitative polymerase chain reaction to quantify the plasma HPV DNA in 40 HPV-positive OPC, 24 HPV-negative head-and-neck cancer patients and 10 non-cancer volunteers. The tumor HPV status was confirmed by p16(INK4a) staining and HPV16/18 polymerase chain reaction or HPV in situ hybridization. A total of 14 patients had serial plasma samples for HPV DNA quantification during radiotherapy.HPV DNA was detectable in the plasma samples of SCC90- and HeLa-bearing mice but not in the controls. It was detected in 65% of the pretreatment plasma samples from HPV-positive OPC patients using E6/7 quantitative polymerase chain reaction. None of the HPV-negative head-and-neck cancer patients or non-cancer controls had detectable HPV DNA. The pretreatment plasma HPV DNA copy number correlated significantly with the nodal metabolic tumor volume (assessed using (18)F-deoxyglucose positron emission tomography). The serial measurements in 14 patients showed a rapid decline in HPV DNA that had become undetectable at radiotherapy completion. In 3 patients, the HPV DNA level had increased to a discernable level at metastasis.Xenograft studies indicated that plasma HPV DNA is released from HPV-positive tumors. Circulating HPV DNA was detectable in most HPV-positive OPC patients. Thus, plasma HPV DNA might be a valuable tool for identifying relapse.

    View details for DOI 10.1016/j.ijrobp.2011.05.061

    View details for Web of Science ID 000300423500003

    View details for PubMedID 21985946

  • Modern Radiation Therapy Techniques for Pancreatic Cancer GASTROENTEROLOGY CLINICS OF NORTH AMERICA Trakul, N., Koong, A. C., Maxim, P. G., Chang, D. T. 2012; 41 (1): 223-?

    Abstract

    Radiation therapy is a rapidly evolving field, and recent technical advances have spurred an increasing number of new treatments as well as marked improvements in previously existing treatments. Despite a growing body of published evidence demonstrating that radiotherapy for the treatment of pancreatic cancer is improving in efficacy and safety, the ultimate effect on patient outcomes remains to be seen. It is an unfortunate fact that the majority of pancreatic cancer patients will ultimately have metastases and succumb to distant disease. Thus, improvements in local tumor control engendered by these recent advances will have little impact on overall survival without the coincident development of better systemic treatment regimens.

    View details for DOI 10.1016/j.gtc.2011.12.011

    View details for Web of Science ID 000301989100016

    View details for PubMedID 22341260

  • Antiangiogenic and Radiation Therapy Early Effects on In Vivo Computed Tomography Perfusion Parameters in Human Colon Cancer Xenografts in Mice INVESTIGATIVE RADIOLOGY Ren, Y., Fleischmann, D., Foygel, K., Molvin, L., Lutz, A. M., Koong, A. C., Jeffrey, R. B., Tian, L., Willmann, J. K. 2012; 47 (1): 25-32

    Abstract

    To assess early treatment effects on computed tomography (CT) perfusion parameters after antiangiogenic and radiation therapy in subcutaneously implanted, human colon cancer xenografts in mice and to correlate in vivo CT perfusion parameters with ex vivo assays of tumor vascularity and hypoxia.Dynamic contrast-enhanced CT (perfusion CT, 129 mAs, 80 kV, 12 slices × 2.4 mm; 150 ?L iodinated contrast agent injected at a rate of 1 mL/min intravenously) was performed in 100 subcutaneous human colon cancer xenografts on baseline day 0. Mice in group 1 (n=32) received a single dose of the antiangiogenic agent bevacizumab (10 mg/kg body weight), mice in group 2 (n=32) underwent a single radiation treatment (12 Gy), and mice in group 3 (n=32) remained untreated. On days 1, 3, 5, and 7 after treatment, 8 mice from each group underwent a second CT perfusion scan, respectively, after which tumors were excised for ex vivo analysis. Four mice were killed after baseline scanning on day 0 for ex vivo analysis. Blood flow (BF), blood volume (BV), and flow extraction product were calculated using the left ventricle as an arterial input function. Correlation of in vivo CT perfusion parameters with ex vivo microvessel density and extent of tumor hypoxia were assessed by immunofluorescence. Reproducibility of CT perfusion parameter measurements was calculated in an additional 8 tumor-bearing mice scanned twice within 5 hours with the same CT perfusion imaging protocol.The intraclass correlation coefficients for BF, BV, and flow extraction product from repeated CT perfusion scans were 0.93 (95% confidence interval: 0.78, 0.97), 0.88 (0.66, 0.95), and 0.88 (0.56, 0.95), respectively. Changes in perfusion parameters and tumor volumes over time were different between treatments. After bevacizumab treatment, all 3 perfusion parameters significantly decreased from day 1 (P ? 0.006) and remained significantly decreased until day 7 (P ? 0.008); tumor volume increased significantly only on day 7 (P=0.04). After radiation treatment, all 3 perfusion parameters decreased significantly on day 1 (P < 0.001); BF and flow extraction product increased again on day 3 and 5, although without reaching statistically significant difference; and tumor volumes did not change significantly at all time points (P ? 0.3). In the control group, all 3 perfusion parameters did not change significantly, whereas tumor volume increased significantly at all the time points, compared with baseline (P ? 0.04). Ex vivo immunofluorescent staining showed good correlation between all 3 perfusion parameters and microvessel density (?=0.71, 0.66, and 0.69 for BF, BV, and flow extraction product, respectively; P < 0.001). There was a trend toward negative correlation between extent of hypoxia and all 3 perfusion parameters (?=-0.53, -0.47, and -0.40 for BF, BV, and flow extraction product, respectively; P ? 0.05).CT perfusion allows a reproducible, noninvasive assessment of tumor vascularity in human colon cancer xenografts in mice. After antiangiogenic and radiation therapy, BF, BV, and flow extraction product significantly decrease and change faster than the tumor volume.

    View details for DOI 10.1097/RLI.0b013e31823a82f6

    View details for Web of Science ID 000298400100006

    View details for PubMedID 22178893

  • A Novel Aldehyde Dehydrogenase-3 Activator Leads to Adult Salivary Stem Cell Enrichment In Vivo CLINICAL CANCER RESEARCH Banh, A., Xiao, N., Cao, H., Chen, C., Kuo, P., Krakow, T., Bavan, B., Khong, B., Yao, M., Ha, C., Kaplan, M. J., Sirjani, D., Jensen, K., Kong, C. S., Mochly-Rosen, D., Koong, A. C., Quynh-Thu Le, Q. T. 2011; 17 (23): 7265-7272

    Abstract

    To assess aldehyde dehydrogenase (ALDH) expression in adult human and murine submandibular gland (SMG) stem cells and to determine the effect of ALDH3 activation in SMG stem cell enrichment.Adult human and murine SMG stem cells were selected by cell surface markers (CD34 for human and c-Kit for mouse) and characterized for various other stem cell surface markers by flow cytometry and ALDH isozymes expression by quantitative reverse transcriptase PCR. Sphere formation and bromodeoxyuridine (BrdUrd) incorporation assays were used on selected cells to confirm their renewal capacity and three-dimensional (3D) collagen matrix culture was applied to observe differentiation. To determine whether ALDH3 activation would increase stem cell yield, adult mice were infused with a novel ALDH3 activator (Alda-89) or with vehicle followed by quantification of c-Kit(+)/CD90(+) SMG stem cells and BrdUrd(+) salispheres.More than 99% of CD34(+) huSMG stem cells stained positive for c-Kit, CD90 and 70% colocalized with CD44, Nestin. Similarly, 73.8% c-Kit(+) mSMG stem cells colocalized with Sca-1, whereas 80.7% with CD90. Functionally, these cells formed BrdUrd(+) salispheres, which differentiated into acinar- and ductal-like structures when cultured in 3D collagen. Both adult human and murine SMG stem cells showed higher expression of ALDH3 than in their non-stem cells and 84% of these cells have measurable ALDH1 activity. Alda-89 infusion in adult mice significantly increased c-Kit(+)/CD90(+) SMG population and BrdUrd(+) sphere formation compared with control.This is the first study to characterize expression of different ALDH isozymes in SMG stem cells. In vivo activation of ALDH3 can increase SMG stem cell yield, thus providing a novel means for SMG stem cell enrichment for future stem cell therapy.

    View details for DOI 10.1158/1078-0432.CCR-11-0179

    View details for Web of Science ID 000298133600009

    View details for PubMedID 21998334

  • Stereotactic Body Radiotherapy for Colorectal Liver Metastases A Pooled Analysis CANCER Chang, D. T., Swaminath, A., Kozak, M., Weintraub, J., Koong, A. C., Kim, J., Dinniwell, R., Brierley, J., Kavanagh, B. D., Dawson, L. A., Schefter, T. E. 2011; 117 (17): 4060-4069

    Abstract

    This study was undertaken to determine outcomes of stereotactic body radiotherapy for colorectal liver metastases in a pooled patient cohort.Patients with colorectal liver metastases from 3 institutions were included if they had 1 to 4 lesions, received 1 to 6 fractions of stereotactic body radiotherapy, and had radiologic imaging ? 3 months post-treatment. Sixty-five patients with 102 lesions treated from August 2003 to May 2009 were retrospectively analyzed. A tumor control probability (TCP) model was used to estimate the 3-fraction dose required for > 90% local control after converting the schedule into biologically equivalent dose (BED), single-fraction equivalent dose, or linear quadratic model-based single-fraction dose.Forty-seven (72%) patients had ? 1 chemotherapy regimen before stereotactic body radiotherapy, and 27 (42%) patients had ? 2 regimens. The median follow-up was 1.2 years (range, 0.3-5.2 years). The median dose was 42 gray (Gy; range, 22-60 Gy). When evaluated separately by multivariate analysis, total dose (P = .0015), dose/fraction (P = .003), and BED (P = .004) all correlated with local control by lesion. On multivariate analysis, nonactive extrahepatic disease was associated with overall survival (OS; P = .046), and sustained local control was closely correlated (P = .06). By using single-fraction equivalent dose, BED, or linear quadratic model-based single-fraction dose in the TCP model, the estimated dose range needed for 1-year local control > 90% is 46 to 52 Gy in 3 fractions.Liver stereotactic body radiotherapy is well tolerated and effective for colorectal liver metastases. The strong correlation between local control and OS supports controlling hepatic disease even for heavily pretreated patients. For a 3-fraction regimen of stereotactic body radiotherapy, a prescription dose of ? 48 Gy should be considered, if normal tissue constraints allow.

    View details for DOI 10.1002/cncr.25997

    View details for Web of Science ID 000294924800030

    View details for PubMedID 21432842

  • Intensity-Modulated Radiation Therapy Versus Conventional Radiation Therapy for Squamous Cell Carcinoma of the Anal Canal CANCER Bazan, J. G., Hara, W., Hsu, A., Kunz, P. A., Ford, J., Fisher, G. A., Welton, M. L., Shelton, A., Kapp, D. S., Koong, A. C., Goodman, K. A., Chang, D. T. 2011; 117 (15): 3342-3351

    Abstract

    The purpose of this study was to compare outcomes in patients with anal canal squamous cell carcinoma (SCCA) who were treated with definitive chemoradiotherapy by either intensity-modulated radiation therapy (IMRT) or conventional radiotherapy (CRT).Forty-six patients who received definitive chemoradiotherapy from January 1993 to August 2009 were included. Forty-five patients received 5-fluorouracil with mitomycin C (n = 39) or cisplatin (n = 6). Seventeen (37%) were treated with CRT and 29 (63%) with IMRT. The median dose was 54 Gy in both groups. Median follow-up was 26 months (CRT) and 32 months (IMRT). T3-T4 stage (P = .18) and lymph node-positive disease (P = .6) were similar between groups.The CRT group required longer treatment duration (57 days vs 40 days, P < .0001), more treatment breaks (88% vs 34.5%, P = .001), and longer breaks (12 days vs 1.5 days, P < .0001) than patients treated with IMRT. Eleven (65%) patients in the CRT group experienced grade >2 nonhematologic toxicity compared with 6 (21%) patients in the IMRT group (P = .003). The 3-year overall survival (OS), locoregional control (LRC), and progression-free survival were 87.8%, 91.9%, and 84.2%, respectively, for the IMRT groups and 51.8%, 56.7%, and 56.7%, respectively, for the CRT group (all P < .01). On multivariate analysis, T stage, use of IMRT, and treatment duration were associated with OS, and T stage and use of IMRT were associated with LRC.The use of IMRT was associated with less toxicity, reduced need for treatment breaks, and excellent LRC and OS compared with CRT in patients with SCCA of the anal canal.

    View details for DOI 10.1002/cncr.25901

    View details for Web of Science ID 000293103800008

    View details for PubMedID 21287530

  • Tumor Galectin-1 Mediates Tumor Growth and Metastasis through Regulation of T-Cell Apoptosis CANCER RESEARCH Banh, A., Zhang, J., Cao, H., Bouley, D. M., Kwok, S., Kong, C., Giaccia, A. J., Koong, A. C., Le, Q. 2011; 71 (13): 4423-4431

    Abstract

    Galectin-1 (Gal-1), a carbohydrate-binding protein whose secretion is enhanced by hypoxia, promotes tumor aggressiveness by promoting angiogenesis and T-cell apoptosis. However, the importance of tumor versus host Gal-1 in tumor progression is undefined. Here we offer evidence that implicates tumor Gal-1 and its modulation of T-cell immunity in progression. Comparing Gal-1-deficient mice as hosts for Lewis lung carcinoma cells where Gal-1 levels were preserved or knocked down, we found that tumor Gal-1 was more critical than host Gal-1 in promoting tumor growth and spontaneous metastasis. Enhanced growth and metastasis associated with Gal-1 related to its immunomodulatory function, insofar as the benefits of Gal-1 expression to Lewis lung carcinoma growth were abolished in immunodeficient mice. In contrast, angiogenesis, as assessed by microvessel density count, was similar between tumors with divergent Gal-1 levels when examined at a comparable size. Our findings establish that tumor rather than host Gal-1 is responsible for mediating tumor progression through intratumoral immunomodulation, with broad implications in developing novel targeting strategies for Gal-1 in cancer.

    View details for DOI 10.1158/0008-5472.CAN-10-4157

    View details for Web of Science ID 000292287300013

    View details for PubMedID 21546572

  • Unfolded Protein Response Regulation in Keloid Cells JOURNAL OF SURGICAL RESEARCH Butler, P. D., Wang, Z., Ly, D. P., Longaker, M. T., Koong, A. C., Yang, G. P. 2011; 167 (1): 151-157

    Abstract

    Keloids are a common form of pathologic wound healing characterized by excessive production of extracellular matrix. The unfolded protein response (UPR) is a cellular response to hypoxia, a component of the wound microenvironment, capable of protecting cells from the effects of over-accumulation of misfolded proteins. Since keloids have hypersecretion of extracellular matrix, we hypothesized that keloid fibroblasts (KFs) may have enhanced activation of the UPR compared with normal fibroblasts (NFs).KFs and NFs were placed in a hypoxia chamber for 0, 24, and 48h. We also used tunicamycin to specifically up-regulate the UPR. UPR activation was assayed by PCR for xbp-1 splicing and by immunoblotting with specific antibodies for the three UPR transducers. Nuclear localization of XBP-1 protein in KFs was confirmed by immunofluorescence.There is increased activation of XBP-1 protein in KFs compared with NFs following exposure to hypoxia. Pancreatic ER kinase (PERK) and ATF-6, two other pathways activated by the UPR, show comparable activation between KFs and NFs. We confirmed that there is enhanced activation of XBP-1 by demonstrating increased nuclear localization of XBP-1 using immunofluorescence.In contrast to our initial hypothesis that keloids would have broad activation of the UPR, we demonstrate here that there is a specific up-regulation of one facet of the UPR response. This may represent a specific molecular defect in KFs compared with NFs, and also suggests modulation of the UPR can be used in wound healing therapy.

    View details for DOI 10.1016/j.jss.2009.04.036

    View details for Web of Science ID 000288744100029

    View details for PubMedID 19631342

  • Stereotactic Body Radiation Therapy for Gastrointestinal Malignancies IMRT IGRT SBRT- ADVANCES IN THE TREATMENT PLANNING AND DELIVERY OF RADIOTHERAPY Minn, A. Y., Koong, A. C., Chang, D. T. 2011; 43: 412-427

    Abstract

    Stereotactic body radiotherapy (SBRT) is an emerging treatment for pancreas cancer and liver tumors. Early data suggest excellent control rates for locally advanced pancreas cancer. However, due to the close proximity of the duodenum and stomach, steps to effectively minimize toxicities must be taken through image guidance of treatments. SBRT for liver tumors has also shown high rates of local control with low risks for hepatic toxicity. Careful selection of cases for SBRT is essential to achieve disease control and to minimize toxicity for patients. In treatment, attention must be paid to minimizing exposure of nearby normal tissues, including ribs, skin and bowel as well as the functioning organs surrounding the tumors. There is no accepted standard for the SBRT dose/fractionation schedule for these cases and the optimal strategy will likely depend on the size, number and location of lesions for each patient. However, the published data seem to suggest an overall dose-response effect. To realize the clinical potential of SBRT for these tumors, investigations are needed to determine optimum fractionation schedules and to integrate its use with systemic chemotherapy programs.

    View details for Web of Science ID 000292117400021

    View details for PubMedID 21625166

  • Orthovoltage intraoperative radiation therapy for pancreatic adenocarcinoma RADIATION ONCOLOGY Bachireddy, P., Tseng, D., Horoschak, M., Chang, D. T., Koong, A. C., Kapp, D. S., Tran, P. T. 2010; 5

    Abstract

    To analyze the outcomes of patients from a single institution treated with surgery and orthovoltage intraoperative radiotherapy (IORT) for pancreatic adenocarcinoma.We retrospectively reviewed 23 consecutive patients from 1990-2001 treated with IORT to 23 discrete sites with median and mean follow up of 6.5 and 21 months, respectively. Most tumors were located in the head of the pancreas (83%) and sites irradiated included: tumor bed (57%), vessels (26%), both the tumor bed/vessels (13%) and other (4%). The majority of patients (83%) had IORT at the time of their definitive surgery. Three patients had preoperative chemoradiation (13%). Orthovoltage X-rays (200-250 kVp) were employed via individually sized and beveled cone applicators. Additional mean clinical characteristics include: age 64 (range 41-81); tumor size 4 cm (range 1.4-11); and IORT dose 1106 cGy (range 600-1500). Post-operative external beam radiation (EBRT) or chemotherapy was given to 65% and 76% of the assessable patients, respectively. Outcomes measured were infield control (IFC), loco-regional control (LRC), distant metastasis free survival (DMFS), overall survival (OS) and treatment-related complications.Kaplan-Meier (KM) 2-year IFC, LRC, DMFS and OS probabilities for the whole group were 83%, 61%, 26%, and 27%, respectively. Our cohort had three grade 3-5 complications associated with treatment (surgery and IORT).Orthovoltage IORT following tumor reductive surgery is reasonably well tolerated and seems to confer in-field control in carefully selected patients. However, distant metastases remain the major problem for patients with pancreatic adenocarcinoma.

    View details for DOI 10.1186/1748-717X-5-105

    View details for Web of Science ID 000284380900001

    View details for PubMedID 21059255

  • Pathological response after chemoradiation for T3 rectal cancer. Colorectal disease Chennupati, S. K., Kamaya, A., Fisher, G. A., Ford, J. M., Kunz, P., Itakura, H., Welton, M. L., Shelton, A., Van Dam, J., Koong, A. C., Chang, D. T. 2010; 12 (7 Online): e24-30

    Abstract

    The aim of this study was to investigate the effect of preoperative chemoradiotherapy (CRT) on nodal disease in locally advanced rectal adenocarcinoma.Thirty-two patients staged uT3N0 and 27 patients staged uT3N1 rectal adenocarcinoma who underwent pre-CRT staging using endoscopic ultrasound or rectal protocol CT were included. The median radiation dose was 50.4 Gy (range: 45-50.4 Gy) at 1.8 Gy per fraction and all patients received concurrent 5-FU or capecitabine-based chemotherapy. Low anterior resection or abdomino-perineal resection occurred at a median of 46 days (range: 27-112 days) after CRT.Eleven of 32 uT3N0 patients (34.4%) and 13 of 26 uT3N1 patients (50.0%) had ypN+ (P = 0.29). For patients with uT3N0, 10 of 20 (50.0%) with ypT2-3 and 1 of 12 (8.3%) with ypT0-1 were ypN+ (P = 0.02). For patients with uT3N1, 12 of 20 (60.0%) with ypT2-3 and 1 of 6 (16.7%) with ypT0-1 were ypN+ (P = 0.16). Overall, the ypN+ rate was 11.1% in the ypT0-yT1 group compared with 55.0% in the ypT2-yT3 group (P = 003). Among patients with uT3N0 disease, the ypN+ rate in patients who had surgery > 46 days vs 46 days vs 46 days vs

    View details for DOI 10.1111/j.1463-1318.2009.02013.x

    View details for PubMedID 19614668

  • Cetuximab-Based Immunotherapy and Radioimmunotherapy of Head and Neck Squamous Cell Carcinoma CLINICAL CANCER RESEARCH Niu, G., Sun, X., Cao, Q., Courter, D., Koong, A., Le, Q., Gambhir, S. S., Chen, X. 2010; 16 (7): 2095-2105

    Abstract

    To show the relationship between antibody delivery and therapeutic efficacy in head and neck cancers, in this study we evaluated the pharmacokinetics and pharmacodynamics of epidermal growth factor receptor (EGFR)-targeted immunotherapy and radioimmunotherapy by quantitative positron emission tomography (PET) imaging.EGFR expression on UM-SCC-22B and SCC1 human head and neck squamous cell cancer (HNSCC) cells were determined by flow cytometry and immunostaining. Tumor delivery and distribution of cetuximab in tumor-bearing nude mice were evaluated with small animal PET using (64)Cu-DOTA-cetuximab. The in vitro toxicity of cetuximab to HNSCC cells was evaluated by MTT assay. The tumor-bearing mice were then treated with four doses of cetuximab at 10 mg/kg per dose, and tumor growth was evaluated by caliper measurement. FDG PET was done after the third dose of antibody administration to evaluate tumor response. Apoptosis and tumor cell proliferation after cetuximab treatment were analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and Ki-67 staining. Radioimmunotherapy was done with (90)Y-DOTA-cetuximab.EGFR expression on UM-SCC-22B cells is lower than that on SCC1 cells. However, the UM-SCC-22B tumors showed much higher (64)Cu-DOTA-cetuximab accumulation than the SCC1 tumors. Cetuximab-induced apoptosis in SCC1 tumors and tumor growth was significantly inhibited, whereas an agonistic effect of cetuximab on UM-SCC-22B tumor growth was observed. After cetuximab treatment, the SCC1 tumors showed decreased FDG uptake, and the UM-SCC-22B tumors had increased FDG uptake. UM-SCC-22B tumors are more responsive to (90)Y-DOTA-cetuximab treatment than SCC1 tumors, partially due to the high tumor accumulation of the injected antibody.Cetuximab has an agonistic effect on the growth of UM-SCC-22B tumors, indicating that tumor response to cetuximab treatment is not necessarily related to EGFR expression and antibody delivery efficiency, as determined by PET imaging. Although PET imaging with antibodies as tracers has limited function in patient screening, it can provide guidance for targeted therapy using antibodies as delivery vehicles.

    View details for DOI 10.1158/1078-0432.CCR-09-2495

    View details for Web of Science ID 000278595800013

    View details for PubMedID 20215534

  • Circulating miR-210 as a Novel Hypoxia Marker in Pancreatic Cancer TRANSLATIONAL ONCOLOGY Ho, A. S., Huang, X., Cao, H., Christman-Skieller, C., Bennewith, K., Le, Q., Koong, A. C. 2010; 3 (2): 109-113

    Abstract

    MicroRNA are small noncoding transcripts involved in many cellular mechanisms, including tumorigenesis. miR-210, in particular, is induced by hypoxia and correlates with adverse outcomes in certain cancers. Because pancreatic adenocarcinomas exhibit extremely hypoxic signatures, we hypothesized that miR-210 may serve as a diagnostic marker for screening or surveillance for pancreatic cancer. Plasma samples were obtained from newly diagnosed pancreatic cancer patients and age-matched noncancer controls. miRNA was extracted directly from plasma and reverse-transcribed to complementary DNA. A known quantity of synthetic Caenorhabditis elegans miR-54 (celmiR-54) was added for normalization. miR-210 and cel-miR-54 were then measured using quantitative reverse transcription polymerase chain reaction. An initial cohort of 11 pancreatic cancer patients and 14 age-matched controls was used as the test set and a second cohort of 11 pancreatic cancer patients and 11 controls was used as the validating set in this study. miR-210 was reliably detected and quantified, with a statistically significant four-fold increase in expression in pancreatic cancer patients compared with normal controls (P < .00004) in the test set. This difference was confirmed in the validation group (P < .018). In summary, circulating miR-210 levels are elevated in pancreatic cancer patients and may potentially serve as a useful biomarker for pancreatic cancer diagnosis.

    View details for DOI 10.1593/tlo.09256

    View details for Web of Science ID 000278912800005

    View details for PubMedID 20360935

  • The RGD Domain of Human Osteopontin Promotes Tumor Growth and Metastasis through Activation of Survival Pathways PLOS ONE Courter, D., Cao, H., Kwok, S., Kong, C., Banh, A., Kuo, P., Bouley, D. M., Vice, C., Brustugun, O. T., Denko, N. C., Koong, A. C., Giaccia, A., Le, Q. 2010; 5 (3)

    Abstract

    Human osteopontin (OPN), a known tumor associated protein, exists in different isoforms, whose function is unclear. It also possesses a RGD domain, which has been implicated in diverse function. Here, we use genetic approaches to systematically investigate the function of the RGD domain in different OPN isoforms on tumor progression and metastasis for 2 different solid tumor models.Using isoform-specific qRT-PCR, we found that OPN-A and B were the main isoforms overexpressed in evaluated human tumors, which included 4 soft tissue sarcomas, 24 lung and 30 head and neck carcinomas. Overexpression of either OPN-A or B in two different cell types promoted local tumor growth and lung metastasis in SCID mouse xenografts. However, expression of either isoform with the RGD domain either mutated or deleted decreased tumor growth and metastasis, and resulted in increased apoptosis by TUNEL staining. In vitro, whereas mutation of the RGD domain did not affect cell-cell adhesion, soft agar growth or cell migration, it increased apoptosis under hypoxia and serum starvation. This effect could be mitigated when the RGD mutant cells were treated with condition media containing WT OPN. Mechanistically, the RGD region of OPN inhibited apoptosis by inducing NF-kappaB activation and FAK phosphorylation. Inhibition of NF-kappaB (by siRNA to the p65 subunit) or FAK activation (by a inhibitor) significantly increased apoptosis under hypoxia in WT OPN cells, but not in RGD mutant cells.Unlike prior reports, our data suggest that the RGD domain of both OPN-A and B promote tumor growth and metastasis mainly by protecting cells against apoptosis under stressed conditions and not via migration or invasion. Future inhibitors directed against OPN should target multiple isoforms and should inhibit cell survival mechanisms that involve the RGD domain, FAK phosphorylation and NF-kappaB activation.

    View details for DOI 10.1371/journal.pone.0009633

    View details for Web of Science ID 000275328800027

    View details for PubMedID 20224789

  • EUS-guided gold fiducial insertion for image-guided radiation therapy of pancreatic cancer: 50 successful cases without fluoroscopy GASTROINTESTINAL ENDOSCOPY Park, W. G., Yan, B. M., Schellenberg, D., Kim, J., Chang, D. T., Koong, A., Patalano, C., Van Dam, J. 2010; 71 (3): 513-518

    Abstract

    Image-guided radiation therapy (IGRT) accurately delivers a high dose of potentially tumoricidal radiation to its target while sparing adjacent healthy tissue. Application of IGRT to unresectable pancreatic cancer requires the use of fiducials to track the precise location of the tumor. Fiducial markers have been successfully placed endoscopically.To determine the feasibility of EUS-guided gold fiducial placement for IGRT.Prospective case series.Tertiary medical center.Consecutively referred patients with locally advanced unresectable pancreatic adenocarcinoma for EUS-guided insertion of gold fiducials from December 2006 to February 2009.Under only EUS guidance, fiducial markers were deployed into or near the tumor by using a 19-gauge needle. In most cases, a sterile water injection technique was used to insert the fiducials. Fluoroscopy was not used in any case.Successful placement of an adequate number of fiducials to proceed with IGRT as determined by CT.Fifty-seven consecutive patients were included. Fifty cases (88%) were successful. Of the cases in which fiducial placement was attempted and follow-up was adequate, 94% (50 of 53) of cases were successful.Single-center, nonrandomized study.EUS-guided fine-needle insertion was safe and effective in delivering gold fiducial markers for image-guided radiation therapy. Fluoroscopy was not required for successful fiducial placement.

    View details for DOI 10.1016/j.gie.2009.10.030

    View details for Web of Science ID 000275897900012

    View details for PubMedID 20189509

  • INTERFRACTIONAL UNCERTAINTY IN THE TREATMENT OF PANCREATIC CANCER WITH RADIATION INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Jayachandran, P., Minn, A. Y., Van Dam, J., Norton, J. A., Koong, A. C., Chang, D. T. 2010; 76 (2): 603-607

    Abstract

    To compare the interfractional variation in pancreatic tumor position using bony anatomy and implanted fiducial markers.Five consecutively treated patients with pancreatic adenocarcinoma who received definitive intensity-modulated radiation therapy at Stanford University (Stanford, CA) underwent fiducial seed placement and treatment on the Varian Trilogy system (Varian, Palo Alto, CA) with respiratory gating. Daily orthogonal kilovoltage imaging was performed to verify patient positioning, and isocenter shifts were made initially to match bony anatomy. Next, a final shift to the fiducial seeds was made under fluoroscopic guidance to confirm the location of the pancreatic tumor during the respiratory gated phase. All shifts were measured along three axes, left (+)-right (-), anterior (-)-posterior (+), and superior (+)-inferior (-), and the overall interfractional tumor movement was calculated based on these values.A total of 140 fractions were analyzed. The mean absolute shift to fiducial markers after shifting to bony anatomy was 1.6 mm (95th percentile, 7 mm; range, 0-9 mm), 1.8 mm (95th percentile, 7 mm; range, 0-13 mm), and 4.1 mm (95th percentile, 12 mm; range, 0-19 mm) in the anterior-posterior, left-right, and superior-inferior directions, respectively. The mean interfractional vector shift distance was 5.5 mm (95th percentile, 14.5 mm; range, 0-19.3 mm). In 28 of 140 fractions (20%) no fiducial shift was required after alignment to bony anatomy.There is substantial residual uncertainty after alignment to bony anatomy when radiating pancreatic tumors using respiratory gating. Bony anatomy matched tumor position in only 20% of the radiation treatments. If bony alignment is used in conjunction with respiratory gating without implanted fiducials, treatment margins need to account for this uncertainty.

    View details for DOI 10.1016/j.ijrobp.2009.06.029

    View details for Web of Science ID 000274121500040

    View details for PubMedID 19879062

  • Multimodality treatment with intensity modulated radiation therapy for esophageal cancer DISEASES OF THE ESOPHAGUS La, T. H., Minn, A. Y., Su, Z., Fisher, G. A., Ford, J. M., Kunz, P., Goodman, K. A., Koong, A. C., Chang, D. T. 2010; 23 (4): 300-308

    Abstract

    The objective of this study is to determine the feasibility and report the outcome of patients with locally advanced esophageal cancer treated with preoperative or definitive chemoradiotherapy (CRT) using intensity-modulated radiation therapy (IMRT). Between 2003 and 2007, 30 patients with non-cervical esophageal cancer received concurrent chemotherapy and IMRT at Stanford University. Eighteen patients were planned for definitive CRT and 12 were planned for preoperative CRT. All patients had computed tomography-based treatment planning and received IMRT. The median dose delivered was 50.4 Gy. Patients planned for preoperative CRT underwent surgery 4-13 weeks (median 8.3 weeks) following completion of CRT. Median follow-up of surviving patients from start of RT was 24.2 months (range 8.2-38.3 months). The majority of tumors were adenocarcinomas (67%) and poorly differentiated (57%). Tumor location was 7% upper, 20% mid, 47% lower, and 27% gastroesophageal junction. Actuarial 2-year local-regional control (LRC) was 64%. High tumor grade was an adverse prognostic factor for LRC and overall survival (OS) (P= 0.015 and 0.012, respectively). The 2-year LRC was 83% vs. 51% for patients treated preoperatively vs. definitively (P= 0.32). The 2-year disease-free and OS were 38% and 56%, respectively. Twelve patients (40%) required feeding tube placement, and the average weight loss from baseline was 4.8%. Twelve (40%) patients experienced grade 3+ acute complications and one patient died of complications following feeding tube placement. Three patients (10%) required a treatment break. Eight patients (27%) experienced grade 3 late complications. No grade 4 complications were seen. IMRT was effective and well tolerated. Disease recurrence remains a challenge and further investigation with dose escalation to improve LRC and OS is warranted.

    View details for DOI 10.1111/j.1442-2050.2009.01004.x

    View details for Web of Science ID 000278109300005

    View details for PubMedID 19732129

  • Identification of a biomarker panel using a multiplex proximity ligation assay improves accuracy of pancreatic cancer diagnosis JOURNAL OF TRANSLATIONAL MEDICINE Chang, S. T., Zahn, J. M., Horecka, J., Kunz, P. L., Ford, J. M., Fisher, G. A., Le, Q. T., Chang, D. T., Ji, H., Koong, A. C. 2009; 7

    Abstract

    Pancreatic cancer continues to prove difficult to clinically diagnose. Multiple simultaneous measurements of plasma biomarkers can increase sensitivity and selectivity of diagnosis. Proximity ligation assay (PLA) is a highly sensitive technique for multiplex detection of biomarkers in plasma with little or no interfering background signal.We examined the plasma levels of 21 biomarkers in a clinically defined cohort of 52 locally advanced (Stage II/III) pancreatic ductal adenocarcinoma cases and 43 age-matched controls using a multiplex proximity ligation assay. The optimal biomarker panel for diagnosis was computed using a combination of the PAM algorithm and logistic regression modeling. Biomarkers that were significantly prognostic for survival in combination were determined using univariate and multivariate Cox survival models.Three markers, CA19-9, OPN and CHI3L1, measured in multiplex were found to have superior sensitivity for pancreatic cancer vs. CA19-9 alone (93% vs. 80%). In addition, we identified two markers, CEA and CA125, that when measured simultaneously have prognostic significance for survival for this clinical stage of pancreatic cancer (p < 0.003).A multiplex panel assaying CA19-9, OPN and CHI3L1 in plasma improves accuracy of pancreatic cancer diagnosis. A panel assaying CEA and CA125 in plasma can predict survival for this clinical cohort of pancreatic cancer patients.

    View details for DOI 10.1186/1479-5876-7-105

    View details for Web of Science ID 000272889900001

    View details for PubMedID 20003342

  • Re: "The safety and efficacy of robotic image-guided radiosurgery system treatment for intra- and extracranial lesions: A systematic review of the literature" [Radiotherapy and Oncology 89 (2009) 245-253] RADIOTHERAPY AND ONCOLOGY Gibbs, I. C., Levendag, P. C., Fariselli, L., Bondiau, P., Lartigau, E., Loo, B. W., Gagnon, G. J., Koong, A. 2009; 93 (3): 656-657

    View details for DOI 10.1016/j.radonc.2009.08.024

    View details for Web of Science ID 000272762900048

    View details for PubMedID 19748142

  • Oxygen Consumption Can Regulate the Growth of Tumors, a New Perspective on the Warburg Effect PLOS ONE Chen, Y., Cairns, R., Papandreou, I., Koong, A., Denko, N. C. 2009; 4 (9)

    Abstract

    The unique metabolism of tumors was described many years ago by Otto Warburg, who identified tumor cells with increased glycolysis and decreased mitochondrial activity. However, "aerobic glycolysis" generates fewer ATP per glucose molecule than mitochondrial oxidative phosphorylation, so in terms of energy production, it is unclear how increasing a less efficient process provides tumors with a growth advantage.We carried out a screen for loss of genetic elements in pancreatic tumor cells that accelerated their growth as tumors, and identified mitochondrial ribosomal protein L28 (MRPL28). Knockdown of MRPL28 in these cells decreased mitochondrial activity, and increased glycolysis, but paradoxically, decreased cellular growth in vitro. Following Warburg's observations, this mutation causes decreased mitochondrial function, compensatory increase in glycolysis and accelerated growth in vivo. Likewise, knockdown of either mitochondrial ribosomal protein L12 (MRPL12) or cytochrome oxidase had a similar effect. Conversely, expression of the mitochondrial uncoupling protein 1 (UCP1) increased oxygen consumption and decreased tumor growth. Finally, treatment of tumor bearing animals with dichloroacetate (DCA) increased pyruvate consumption in the mitochondria, increased total oxygen consumption, increased tumor hypoxia and slowed tumor growth.We interpret these findings to show that non-oncogenic genetic changes that alter mitochondrial metabolism can regulate tumor growth through modulation of the consumption of oxygen, which appears to be a rate limiting substrate for tumor proliferation.

    View details for DOI 10.1371/journal.pone.0007033

    View details for Web of Science ID 000269796500017

    View details for PubMedID 19753307

  • Pancreatic Tumor Motion on a Single Planning 4D-CT Does Not Correlate With Intrafraction Tumor Motion During Treatment AMERICAN JOURNAL OF CLINICAL ONCOLOGY-CANCER CLINICAL TRIALS Minn, A. Y., Schellenberg, D., Maxim, P., Suh, Y., McKenna, S., Cox, B., Dieterich, S., Xing, L., Graves, E., Goodman, K. A., Chang, D., Koong, A. C. 2009; 32 (4): 364-368

    Abstract

    To quantify pancreas tumor motion on both a planning 4D-CT and during a single fraction treatment using the CyberKnife linear accelerator and Synchrony respiratory tracking software, and to investigate whether a single 4D-CT study is reliable for determining radiation treatment margins for patients with locally advanced pancreas cancer.Twenty patients underwent fiducial placement, biphasic pancreatic protocol CT scan and 4D-CT scan in the treatment position while free-breathing. Patients were then treated with a single 25 Gy fraction of stereotactic body radiotherapy. Predicted pancreas motion in the superior-inferior (SI), left-right (LR), and anterior-posterior (AP) directions was calculated from the maximum inspiration and maximum expiration 4D-CT scan. For CyberKnife treatments, mean respiratory cycle motion and maximum respiratory cycle motion was determined in the SI, LR, and AP directions.The range of centroid movement based on 4D-CT in the SI, LR, and AP directions were 0.9 to 28.8 mm, 0.1 to 13.7 mm, and 0.2 to 7.6 mm, respectively. During CyberKnife treatment, in the SI direction, the mean motion of the centroid ranged from 0.5 to 12.7 mm. In the LR direction, the mean motion range was 0.4 to 9.4 mm. In the AP direction, the mean motion range was 0.6 to 5.5 mm. The maximum range of movement (mean) during CyberKnife treatment in the SI, LR, and AP directions were 4.5 to 48.8 mm (mean 20.8 mm), 1.5 to 41.3 mm (mean 11.3 mm), and 1.6 to 68.1 mm (mean 13.4 mm), respectively. Neither the maximum or mean motion correlated with the 4D-CT movement.There is substantial respiratory associated motion of pancreatic tumors. The 4D-CT planning scans cannot accurately predict the movement of pancreatic tumors during actual treatment on CyberKnife.

    View details for DOI 10.1097/COC.0b013e31818da9e0

    View details for Web of Science ID 000268761600007

    View details for PubMedID 19398901

  • Treatment of Esophageal Cancer Based on Histology A Surveillance Epidemiology and End Results Analysis AMERICAN JOURNAL OF CLINICAL ONCOLOGY-CANCER CLINICAL TRIALS Chang, D. T., Chapman, C., Shen, J., Su, Z., Koong, A. C. 2009; 32 (4): 405-410

    Abstract

    The majority of esophageal cancer is either adenocarcinoma (ACA) or squamous cell carcinoma (SCCA). Recent randomized trials suggest that definitive chemoradiotherapy may be equally effective as surgery. However, the responsiveness of ACA versus SCCA to radiotherapy (RT) has never been compared. This Surveillance Epidemiology and End Results registry analysis investigates whether survival differed between ACA and SCCA based on the treatment modality.Patients with T2-4N0 or N+ SCCA and ACA in the cervical or thoracic esophagus diagnosed from 1983 to 2004 were obtained from the Surveillance Epidemiology and End Results database. Patients with multiple primary cancers, underwent a surgical procedure other than partial or total esophagectomy, had metastatic or T1N0 disease, or received RT that did not include external beam radiation were excluded. Patients were grouped according to treatment received: RT alone, preoperative RT, any surgery (regardless of use of RT), and surgery alone.A total of 4752 patients were included, 2680 (56%) had ACA and 2072 (44%) had SCCA. After adjusting for age, marital status, cost of living, and race, the overall survival (OS) and cause-specific survival was similar for all treatment groups except the RT-alone group where OS and SCC were superior for ACA. However, no difference in 3- and 5-year OS and cause-specific survival rates for all groups.No difference in survival was seen between patients with ACA and SCCA across any of the major treatment modalities for esophageal cancer, suggesting that both histologies respond to treatment similarly.

    View details for DOI 10.1097/COC.0b013e3181917158

    View details for Web of Science ID 000268761600014

    View details for PubMedID 19415029

  • A Primer on Image-guided Radiation Therapy for the Interventional Radiologist JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kothary, N., Dieterich, S., Louie, J. D., Koong, A. C., Hofmann, L. V., Sze, D. Y. 2009; 20 (7): 859-862

    Abstract

    The use of image-guided radiation therapy in thoracic and abdominal tumors is increasing. Herein, the authors review the process of image-guided radiation therapy and describe techniques useful for optimal implantation of fiducial markers.

    View details for DOI 10.1016/j.jvir.2009.03.037

    View details for Web of Science ID 000267613000001

    View details for PubMedID 19481470

  • Impaired interferon signaling is a common immune defect in human cancer PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Critchley-Thorne, R. J., Simons, D. L., Yan, N., Miyahira, A. K., Dirbas, F. M., Johnson, D. L., Swetter, S. M., Carlson, R. W., Fisher, G. A., Koong, A., Holmes, S., Lee, P. P. 2009; 106 (22): 9010-9015

    Abstract

    Immune dysfunction develops in patients with many cancer types and may contribute to tumor progression and failure of immunotherapy. Mechanisms underlying cancer-associated immune dysfunction are not fully understood. Efficient IFN signaling is critical to lymphocyte function; animals rendered deficient in IFN signaling develop cancer at higher rates. We hypothesized that altered IFN signaling may be a key mechanism of immune dysfunction common to cancer. To address this, we assessed the functional responses to IFN in peripheral blood lymphocytes from patients with 3 major cancers: breast cancer, melanoma, and gastrointestinal cancer. Type-I IFN (IFN-alpha)-induced signaling was reduced in T cells and B cells from all 3 cancer-patient groups compared to healthy controls. Type-II IFN (IFN-gamma)-induced signaling was reduced in B cells from all 3 cancer patient groups, but not in T cells or natural killer cells. Impaired-IFN signaling was equally evident in stage II, III, and IV breast cancer patients, and downstream functional defects in T cell activation were identified. Taken together, these findings indicate that defects in lymphocyte IFN signaling arise in patients with breast cancer, melanoma, and gastrointestinal cancer, and these defects may represent a common cancer-associated mechanism of immune dysfunction.

    View details for DOI 10.1073/pnas.0901329106

    View details for Web of Science ID 000266580500043

    View details for PubMedID 19451644

  • THE RELATIONSHIP BETWEEN HUMAN PAPILLOMAVIRUS STATUS AND OTHER MOLECULAR PROGNOSTIC MARKERS IN HEAD AND NECK SQUAMOUS CELL CARCINOMAS INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Kong, C. S., Narasimhan, B., Cao, H., Kwok, S., Erickson, J. P., Koong, A., Pourmand, N., Le, Q. 2009; 74 (2): 553-561

    Abstract

    To evaluate the relationship between human papillomavirus (HPV) status and known prognostic makers for head and neck cancers including tumor hypoxia, epidermal growth factor receptor (EGFR) expression and intratumoral T-cell levels and to determine the prognostic impact of these markers by HPV status.HPV status in 82 evaluable head and neck squamous cell carcinomas patients was determined by pyrosequencing and related to p16(INK4a) staining and treatment outcomes. It was correlated with tumor hypoxia (tumor pO(2) and carbonic anhydrase [CAIX] staining), EGFR status, and intratumoral lymphocyte expression (CD3 staining).Forty-four percent of evaluable tumors had strong HPV signal by pyrosequencing. There was a significant relationship between strong HPV signal and p16(INK4a) staining as well as oropharynx location. The strong HPV signal group fared significantly better than others, both in time to progression (TTP, p = 0.008) and overall survival (OS, p = 0.004) for all patients and for the oropharyngeal subset. Positive p16(INK4a) staining was associated with better TTP (p = 0.014) and OS (p = 0.00002). There was no relationship between HPV status and tumor pO(2) or CAIX staining. However, HPV status correlated inversely with EGFR reactivity (p = 0.0006) and directly with CD3(+) T-lymphocyte level (p = 0.03). Whereas CAIX and EGFR overexpression were negative prognostic factors regardless of HPV status, CD3(+) T-cell levels was prognostic only in HPV(-) tumors.HPV status was a prognostic factor for progression and survival. It correlated inversely with EGFR expression and directly with T-cell infiltration. The prognostic effect of CAIX and EGFR expression was not influenced by HPV status, whereas intratumoral T-cell levels was significant only for HPV(-) tumors.

    View details for DOI 10.1016/j.ijrobp.2009.02.015

    View details for Web of Science ID 000266057900035

    View details for PubMedID 19427557

  • Detection of Solitary Humeral Metastasis From Pancreatic Adenocarcinoma With F-18 FDG PET/CT CLINICAL NUCLEAR MEDICINE Kim, J., Quon, A., Humke, E., Ford, J. M., Koong, A. C. 2009; 34 (5): 312-313

    View details for Web of Science ID 000265435100015

    View details for PubMedID 19387214

  • Safety and Efficacy of Percutaneous Fiducial Marker Implantation for Image-guided Radiation Therapy JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kothary, N., Heit, J. J., Louie, J. D., Kuo, W. T., Loo, B. W., Koong, A., Chang, D. T., Hovsepian, D., Sze, D. Y., Hofmann, L. V. 2009; 20 (2): 235-239

    Abstract

    To evaluate the safety and technical success rate of percutaneous fiducial marker implantation in preparation for image-guided radiation therapy.From January 2003 to January 2008, we retrospectively reviewed 139 percutaneous fiducial marker implantations in 132 patients. Of the 139 implantations, 44 were in the lung, 61 were in the pancreas, and 34 were in the liver. Procedure-related major and minor complications were documented. Technical success was defined as implantation enabling adequate treatment planning and computed tomographic simulation.The major and minor complication rates were 5% and 17.3%, respectively. Pneumothorax after lung implantation was the most common complication. Pneumothoraces were seen in 20 of the 44 lung implantations (45%); a chest tube was required in only seven of the 44 lung transplantations (16%). Of the 139 implantations, 133 were successful; in six implantations (4.3%) the fiducial markers migrated and required additional procedures or alternate methods of implantation.Percutaneous implantation of fiducial marker is a safe and effective procedure with risks that are similar to those of conventional percutaneous organ biopsy.

    View details for DOI 10.1016/j.jvir.2008.09.026

    View details for Web of Science ID 000263075000012

    View details for PubMedID 19019700

  • Gemcitabine chemotherapy and single-fraction stereotactic body radiotherapy for locally advanced pancreatic cancer INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Schellenberg, D., Goodman, K. A., Lee, F., Chang, S., Kuo, T., Ford, J. M., Fisher, G. A., Quon, A., Desser, T. S., Norton, J., Greco, R., Yang, G. P., Koong, A. C. 2008; 72 (3): 678-686

    Abstract

    Fractionated radiotherapy and chemotherapy for locally advanced pancreatic cancer achieves only modest local control. This prospective trial evaluated the efficacy of a single fraction of 25 Gy stereotactic body radiotherapy (SBRT) delivered between Cycle 1 and 2 of gemcitabine chemotherapy.A total of 16 patients with locally advanced, nonmetastatic, pancreatic adenocarcinoma received gemcitabine with SBRT delivered 2 weeks after completion of the first cycle. Gemcitabine was resumed 2 weeks after SBRT and was continued until progression or dose-limiting toxicity. The gross tumor volume, with a 2-3-mm margin, was treated in a single 25-Gy fraction by Cyberknife. Patients were evaluated at 4-6 weeks, 10-12 weeks, and every 3 months after SBRT.All 16 patients completed SBRT. A median of four cycles (range one to nine) of chemotherapy was delivered. Three patients (19%) developed local disease progression at 14, 16, and 21 months after SBRT. The median survival was 11.4 months, with 50% of patients alive at 1 year. Patients with normal carbohydrate antigen (CA)19-9 levels either at diagnosis or after Cyberknife SBRT had longer survival (p <0.01). Acute gastrointestinal toxicity was mild, with 2 cases of Grade 2 (13%) and 1 of Grade 3 (6%) toxicity. Late gastrointestinal toxicity was more common, with five ulcers (Grade 2), one duodenal stenosis (Grade 3), and one duodenal perforation (Grade 4). A trend toward increased duodenal volumes radiated was observed in those experiencing late effects (p = 0.13).SBRT with gemcitabine resulted in comparable survival to conventional chemoradiotherapy and good local control. However, the rate of duodenal ulcer development was significant.

    View details for DOI 10.1016/j.ijrobp.2008.01.051

    View details for Web of Science ID 000259894300008

    View details for PubMedID 18395362

  • In vivo H-1 magnetic resonance spectroscopy of lactate in patients with Stage IV head and neck squamous cell carcinoma INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Le, Q., Koong, A., Lieskovsky, Y. Y., Narasimhan, B., Graves, E., Pinto, H., Brown, J. M., Spielman, D. 2008; 71 (4): 1151-1157

    Abstract

    To investigate in vivo(1)H magnetic resonance spectroscopy imaging of lactate for assessing tumor hypoxia in head and neck cancers and to determine its utility in predicting the response and outcomes.Volume-localized lactate-edited (1)H magnetic resonance spectroscopy at 1.5 T was performed in vivo on involved neck nodes and control subcutaneous tissues in 36 patients with Stage IV head and neck cancer. The signal intensities (SIs) of lactate, choline, and creatine and the choline/creatine ratio were measured. The tumor partial pressure of oxygen (pO(2)) was obtained in the same lymph node before MRS. Patients were treated with either two cycles of induction chemotherapy (tirapazamine, cisplatin, 5-fluorouracil) followed by simultaneous chemoradiotherapy or the same regimen without tirapazamine. The lactate SI and the choline/creatine ratio correlated with the tumor pO(2), nodal response, and locoregional control.The lactate SI was greater for the involved nodes (median, 0.25) than for the subcutaneous tissue (median, 0.04; p = 0.07). No significant correlation was found between the lactate SI and tumor pO(2) (mean, 0.46 +/- 0.10 for hypoxic nodes [pO(2) < or =10 mm Hg, n = 15] vs. 0.36 +/- 0.07 for nonhypoxic nodes [pO(2) >10 mm Hg, n = 21], p = 0.44). A significant correlation was found between the choline/creatine ratios and tumor pO(2) (mean, 2.74 +/- 0.34 for hypoxic nodes vs. 1.78 +/- 0.31 for nonhypoxic nodes, p = 0.02). No correlation was found between the lactate SI and the complete nodal response (p = 0.52) or locoregional control rates.The lactate SI did not correlate with tumor pO(2), treatment response, or locoregional control. Additional research is needed to refine this technique.

    View details for DOI 10.1016/j.ijrobp.2007.11.030

    View details for Web of Science ID 000257299200025

    View details for PubMedID 18258377

  • High-dose single-fraction radiotherapy: Exploiting a new biology? INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Brown, J. M., Koong, A. C. 2008; 71 (2): 324-325

    View details for DOI 10.1016/j.ijrobp.2008.02.003

    View details for Web of Science ID 000255971100002

    View details for PubMedID 18474308

  • Molecular Imaging of Hypoxia-Inducible Factor 1 alpha and von Hippel-Lindau Interaction in Mice MOLECULAR IMAGING Choi, C. Y., Chau, D. A., Paulmurugan, R., Sutphin, P. D., Le, Q., Koong, A. C., Zundel, W., Gambhir, S. S., Giaccia, A. J. 2008; 7 (3): 139-146

    Abstract

    Tumor hypoxia plays a crucial role in tumorigenesis. Under hypoxia, hypoxia-inducible factor 1 alpha (HIF-1 alpha) regulates activation of genes promoting malignant progression. Under normoxia, HIF-1 alpha is hydroxylated on prolines 402 and 564 and is targeted for ubiquitin-mediated degradation by interacting with the von Hippel-Lindau protein complex (pVHL). We have developed a novel method of studying the interaction between HIF-1 alpha and pVHL using the split firefly luciferase complementation-based bioluminescence system in which HIF-1 alpha and pVHL are fused to amino-terminal and carboxy-terminal fragments of the luciferase, respectively. We demonstrate that hydroxylation-dependent interaction between the HIF-1 alpha and pVHL leads to complementation of the two luciferase fragments, resulting in bioluminescence in vitro and in vivo. Complementation-based bioluminescence is diminished when mutant pVHLs with decreased affinity for binding HIF-1 alpha are used. This method represents a new approach for studying interaction of proteins involved in the regulation of protein degradation.

    View details for DOI 10.2310/7290.2008.00017

    View details for Web of Science ID 000260954700004

    View details for PubMedID 19123984

  • Multiplexed proximity ligation assays to profile putative plasma biomarkers relevant to pancreatic and ovarian cancer CLINICAL CHEMISTRY Fredriksson, S., Horecka, J., Brustugun, O. T., Schlingemann, J., Koong, A. C., Tibshirani, R., Davis, R. W. 2008; 54 (3): 582-589

    Abstract

    Sensitive methods are needed for biomarker discovery and validation. We tested one promising technology, multiplex proximity ligation assay (PLA), in a pilot study profiling plasma biomarkers in pancreatic and ovarian cancer.We used 4 panels of 6- and 7-plex PLAs to detect biomarkers, with each assay consuming 1 microL plasma and using either matched monoclonal antibody pairs or single batches of polyclonal antibody. Protein analytes were converted to unique DNA amplicons by proximity ligation and subsequently detected by quantitative PCR. We profiled 18 pancreatic cancer cases and 19 controls and 19 ovarian cancer cases and 20 controls for the following proteins: a disintegrin and metalloprotease 8, CA-125, CA 19-9, carboxypeptidase A1, carcinoembryonic antigen, connective tissue growth factor, epidermal growth factor receptor, epithelial cell adhesion molecule, Her2, galectin-1, insulin-like growth factor 2, interleukin-1alpha, interleukin-7, mesothelin, macrophage migration inhibitory factor, osteopontin, secretory leukocyte peptidase inhibitor, tumor necrosis factor alpha, vascular endothelial growth factor, and chitinase 3-like 1. Probes for CA-125 were present in 3 of the multiplex panels. We measured plasma concentrations of the CA-125-mesothelin complex by use of a triple-specific PLA with 2 ligation events among 3 probes.The assays displayed consistent measurements of CA-125 independent of which other markers were simultaneously detected and showed good correlation with Luminex data. In comparison to literature reports, we achieved expected results for other putative markers.Multiplex PLA using either matched monoclonal antibodies or single batches of polyclonal antibody should prove useful for identifying and validating sets of putative disease biomarkers and finding multimarker panels.

    View details for DOI 10.1373/clinchem.2007.093195

    View details for Web of Science ID 000253570400019

    View details for PubMedID 18171715

  • Initial evaluation of F-18-fluorothymidine (FLT) PET/CT scanning for primary pancreatic cancer EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING Quon, A., Chang, S. T., Chin, F., Kamaya, A., Dick, D. W., Loo, B. W., Gambhir, S. S., Koong, A. C. 2008; 35 (3): 527-531

    Abstract

    The aim of this study was to evaluate the potential of (18)F-fluorothymidine (FLT) PET/CT for imaging pancreatic adenocarcinoma.This was a pilot study of five patients (four males, one female) with newly diagnosed and previously untreated pancreatic adenocarcinoma. Patients underwent FLT PET/CT, (18)F-fluorodeoxyglucose (FDG) PET/CT, and contrast-enhanced CT scanning before treatment. The presence of cancer was confirmed by histopathological analysis at the time of scanning in all five patients. The degree of FLT and FDG uptake at the primary tumor site was assessed using visual interpretation and semi-quantitative SUV analyses.The primary tumor size ranged from 2.5 x 2.8 cm to 3.5 x 7.0 cm. The SUV of FLT uptake within the primary tumor ranged from 2.1 to 3.1. Using visual interpretation, the primary cancer could be detected from background activity in two of five patients (40%) on FLT PET/CT. By comparison, FDG uptake was higher in each patient with a SUV range of 3.4 to 10.8, and the primary cancer could be detected from background in all five patients (100%).In this pilot study of five patients with primary pancreatic adenocarcinoma, FLT PET/CT scanning showed poor lesion detectability and relatively low levels of radiotracer uptake in the primary tumor.

    View details for DOI 10.1007/s00259-007-0630-z

    View details for Web of Science ID 000254402800010

    View details for PubMedID 17960376

  • Automated contour mapping with a regional deformable model INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Chao, M., Li, T., Schreibmann, E., Koong, A., Xing, L. 2008; 70 (2): 599-608

    Abstract

    To develop a regional narrow-band algorithm to auto-propagate the contour surface of a region of interest (ROI) from one phase to other phases of four-dimensional computed tomography (4D-CT).The ROI contours were manually delineated on a selected phase of 4D-CT. A narrow band encompassing the ROI boundary was created on the image and used as a compact representation of the ROI surface. A BSpline deformable registration was performed to map the band to other phases. A Mattes mutual information was used as the metric function, and the limited memory Broyden-Fletcher-Goldfarb-Shanno algorithm was used to optimize the function. After registration the deformation field was extracted and used to transform the manual contours to other phases. Bidirectional contour mapping was introduced to evaluate the proposed technique. The new algorithm was tested on synthetic images and applied to 4D-CT images of 4 thoracic patients and a head-and-neck Cone-beam CT case.Application of the algorithm to synthetic images and Cone-beam CT images indicates that an accuracy of 1.0 mm is achievable and that 4D-CT images show a spatial accuracy better than 1.5 mm for ROI mappings between adjacent phases, and 3 mm in opposite-phase mapping. Compared with whole image-based calculations, the computation was an order of magnitude more efficient, in addition to the much-reduced computer memory consumption.A narrow-band model is an efficient way for contour mapping and should find widespread application in future 4D treatment planning.

    View details for DOI 10.1016/j.ijrobp.2007.09.057

    View details for Web of Science ID 000252521700038

    View details for PubMedID 18207035

  • Tissue effects after stereotactic body radiotherapy using cyberknife for patients with abdominal malignancies CLINICAL ONCOLOGY Cupp, J. S., Koong, A. C., Fisher, G. A., NORTON, J. A., Goodman, K. A. 2008; 20 (1): 69-75

    Abstract

    To report the tissue effects of treatment with single fraction stereotactic body radiotherapy (SBRT) using Cyberknife on malignant tumours of the abdomen and adjacent normal organs.The data from four autopsies with unresectable pancreatic carcinoma and one lymph node excision from a case of recurrent neuroblastoma were reviewed for radiation-related tissue effects within the primary cancer and the normal organs within the radiation field.Cases of unresectable pancreatic carcinoma consistently showed radiation-induced changes in both the primary tumour and the adjacent, non-malignant colorectal tissue. An additional case of lymph nodes exposed to stereotactic radiation showed typical radiation-related changes, including lymphocyte depletion and capsular fibrosis.A myriad of radiation-related tissue effects are seen after SBRT with Cyberknife. The changes parallel those reported after conventionally fractionated radiotherapy and suggest that the pathophysiological mechanisms of radiation-induced normal tissue damage are similar for biologically equivalent single and fractionated doses of radiotherapy.

    View details for DOI 10.1016/j.clon.2007.08.009

    View details for Web of Science ID 000253281700013

    View details for PubMedID 17900882

  • Enhanced 4D cone-beam CT with inter-phase motion model MEDICAL PHYSICS Li, T., Koong, A., Xing, L. 2007; 34 (9): 3688-3695

    Abstract

    Four-dimensional (4D) cone-beam CT (CBCT) is commonly obtained by respiratory phase binning of the projections, followed by independent reconstructions of the rebinned data in each phase bin. Due to the significantly reduced number of projections per reconstruction, the quality of the 4DCBCT images is often degraded by view-aliasing artifacts easily seen in the axial view. Acquisitions using multiple gantry rotations or slow gantry rotation can increase the number of projections and substantially improve the 4D images. However, the extra cost of the scan time may set fundamental limits to their applications in clinics. Improving the trade-off between image quality and scan time is the key to making 4D onboard imaging practical and more useful. In this article, we present a novel technique toward high-quality 4DCBCT imaging without prolonging the acquisition time, referred to as the "enhanced 4DCBCT". The method correlates the data in different phase bins and integrates the internal motion into the 4DCBCT image formulation. Several strategies of the motion derivation are discussed, and the resultant images are assessed with numerical simulations as well as a clinical case.

    View details for DOI 10.1118/1.2767144

    View details for Web of Science ID 000249547200031

    View details for PubMedID 17926972

  • Expression and prognostic significance of a panel of tissue hypoxia markers in head-and-neck squamous cell carcinomas INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Le, Q., Kong, C., Lavori, P. W., O'Byrne, K., Erler, J. T., Huang, X., Chen, Y., Cao, H., Tibshiran, R., Denko, N., Giaccia, A. J., Koong, A. C. 2007; 69 (1): 167-175

    Abstract

    To investigate the expression pattern of hypoxia-induced proteins identified as being involved in malignant progression of head-and-neck squamous cell carcinoma (HNSCC) and to determine their relationship to tumor pO(2) and prognosis.We performed immunohistochemical staining of hypoxia-induced proteins (carbonic anhydrase IX [CA IX], BNIP3L, connective tissue growth factor, osteopontin, ephrin A1, hypoxia inducible gene-2, dihydrofolate reductase, galectin-1, IkappaB kinase beta, and lysyl oxidase) on tumor tissue arrays of 101 HNSCC patients with pretreatment pO(2) measurements. Analysis of variance and Fisher's exact tests were used to evaluate the relationship between marker expression, tumor pO(2), and CA IX staining. Cox proportional hazard model and log-rank tests were used to determine the relationship between markers and prognosis.Osteopontin expression correlated with tumor pO(2) (Eppendorf measurements) (p = 0.04). However, there was a strong correlation between lysyl oxidase, ephrin A1, and galectin-1 and CA IX staining. These markers also predicted for cancer-specific survival and overall survival on univariate analysis. A hypoxia score of 0-5 was assigned to each patient, on the basis of the presence of strong staining for these markers, whereby a higher score signifies increased marker expression. On multivariate analysis, increasing hypoxia score was an independent prognostic factor for cancer-specific survival (p = 0.015) and was borderline significant for overall survival (p = 0.057) when adjusted for other independent predictors of outcomes (hemoglobin and age).We identified a panel of hypoxia-related tissue markers that correlates with treatment outcomes in HNSCC. Validation of these markers will be needed to determine their utility in identifying patients for hypoxia-targeted therapy.

    View details for DOI 10.1016/j.ijrobp.2007.01.071

    View details for Web of Science ID 000248978300024

    View details for PubMedID 17707270

  • Quantitative PET of EGFR expression in xenograft-bearing mice using Cu-64-labeled cetuximab, a chimeric anti-EGFR monoclonal antibody EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING Cai, W., Chen, K., He, L., Cao, Q., Koong, A., Chen, X. 2007; 34 (6): 850-858

    Abstract

    Cetuximab, a chimeric monoclonal antibody targeting epidermal growth factor receptor (EGFR) on the surface of cancer cells, was approved by the FDA to treat patients with metastatic colorectal cancer. It is currently also in advanced-stage development for the treatment of several other solid tumors. Here we report for the first time the quantitative positron emission tomography (PET) imaging of EGFR expression in xenograft-bearing mice using 64Cu-labeled cetuximab.We conjugated cetuximab with macrocyclic chelating agent 1,4,7,10-tetraazadodecane-N,N',N'',N'''-tetraacetic acid (DOTA), labeled with 64Cu, and tested the resulting 64Cu-DOTA-cetuximab in seven xenograft tumor models. The tracer uptake measured by PET was correlated with the EGFR expression quantified by western blotting. The estimated human dosimetry based on the PET data in Sprague-Dawley rats was also calculated.MicroPET imaging showed that 64Cu-DOTA-cetuximab had increasing tumor activity accumulation over time in EGFR-positive tumors but relatively low uptake in EGFR-negative tumors at all times examined (<5%ID/g). There was a good correlation (R2=0.80) between the tracer uptake (measured by PET) and the EGFR expression level (measured by western blotting). Human dosimetry estimation indicated that the tracer may be safely administered to human patients for tumor diagnosis, with the dose-limiting organ being the liver.The success of EGFR-positive tumor imaging using 64Cu-DOTA-cetuximab can be translated into the clinic to characterize the pharmacokinetics, to select the right population of patients for EGFR-targeted therapy, to monitor the therapeutic efficacy of anti-EGFR treatment, and to optimize the dosage of either cetuximab alone or cetuximab in combination with other therapeutic agents.

    View details for DOI 10.1007/s00259-006-0361-6

    View details for Web of Science ID 000246592300006

    View details for PubMedID 17262214

  • Evaluation of patterns of failure and subjective salivary function in patients treated with intensity modulated radiotherapy for head and neck squamous cell carcinoma HEAD AND NECK-JOURNAL FOR THE SCIENCES AND SPECIALTIES OF THE HEAD AND NECK Daly, M. E., Lieskovsky, Y., Pawlicki, T., Yau, J., Pinto, H., Kaplan, M., Fee, W. E., Koong, A., Goffinet, D. R., Xing, L., Le, Q. 2007; 29 (3): 211-220

    Abstract

    Our aim was to correlate patterns of failure with target volume delineations in patients with head and neck squamous cell carcinoma (HNSCC) treated with intensity-modulated radiation therapy (IMRT) and to report subjective xerostomia outcomes after IMRT as compared with conventional radiation therapy (CRT).Between January 2000 and April 2005, 69 patients with newly diagnosed nonmetastatic HNSCC underwent curative parotid-sparing IMRT at Stanford University. Sites included were oropharynx (n = 39), oral cavity (n = 8), larynx (n = 8), hypopharynx (n = 8), and unknown primary (n = 6). Forty-six patients received definitive IMRT (66 Gy, 2.2 Gy/fraction), and 23 patients received postoperative IMRT (60.2 Gy, 2.15 Gy/fraction). Fifty-one patients also received concomitant chemotherapy. Posttreatment salivary gland function was evaluated by a validated xerostomia questionnaire in 29 IMRT and 75 matched CRT patients >6 months after completing radiation treatment.At a median follow-up of 25 months for living patients (range, 10-60), 7 locoregional failures were observed, 5 in the gross target or high-risk postoperative volume, 1 in the clinical target volume, and 1 at the junction of the IMRT and supraclavicular fields. The 2-year Kaplan-Meier estimates for locoregional control and overall survival were 92% and 74% for definitive IMRT and 87% and 87% for postoperative IMRT patients, respectively. The mean total xerostomia questionnaire score was significantly better for IMRT than for CRT patients (p = .006).The predominant pattern of failure in IMRT-treated patients is in the gross tumor volume. Parotid sparing with IMRT resulted in less subjective xerostomia and may improve quality of life in irradiated HNSCC patients.

    View details for DOI 10.1002/hed.20505

    View details for Web of Science ID 000244459100002

    View details for PubMedID 17111429

  • Impact of integrated PET/CT on variability of target volume delineation in rectal cancer TECHNOLOGY IN CANCER RESEARCH & TREATMENT Patel, D. A., Chang, S. T., Goodman, K. A., Quon, A., Thorndyke, B., Gambhir, S. S., McMillan, A., Loo, B. W., Koong, A. C. 2007; 6 (1): 31-36

    Abstract

    Several studies have demonstrated substantial variability among individual radiation oncologists in defining target volumes using computed tomography (CT). The objective of this study was to determine the impact of combined positron emission tomography and computed tomography (PET/CT) on inter-observer variability of target volume delineation in rectal cancer. We also compared the relative concordance of two PET imaging tracers, 18F-fluorodeoxyglucose (FDG) and 18F-fluorodeoxythymidine (FLT), against conventional computed tomography (CT). Six consecutive patients with locally advanced rectal cancer were enrolled onto an institutional protocol involving preoperative chemoradiotherapy and correlative studies including FDG- and FLT-PET scans acquired in the treatment position. Using these image data sets, four radiation oncologists independently delineated primary and nodal gross tumor volumes (GTVp and GTVn) for a hypothetical boost treatment. Contours were first defined based on CT alone with observers blinded to the PET images, then based on combined PET/CT. An inter-observer similarity index (SI), ranging from a value of 0 for complete disagreement to 1 for complete agreement of contoured voxels, was calculated for each set of volumes. For primary gross tumor volume (GTVp), the difference in estimated SI between CT and FDG was modest (CT SI = 0.77 vs. FDG SI = 0.81), but statistically significant (p = 0.013). The SI difference between CT and FLT for GTVp was also slight (FLT SI = 0.80) and marginally non-significant (p < 0.082). For nodal gross tumor volume, (GTVn), SI was significantly lower for CT based volumes with an estimated SI of 0.22 compared to an estimated SI of 0.70 for FDG-PET/CT (p < 0.0001) and an estimated SI of 0.70 for FLT-PET/CT (p < 0.0001). Boost target volumes in rectal cancer based on combined PET/CT results in lower inter-observer variability compared with CT alone, particularly for nodal disease. The use of FDG and FLT did not appear to be different from this perspective.

    View details for Web of Science ID 000244732600005

    View details for PubMedID 17241098

  • Stereotactic body radiotherapy for unresectable pancreatic cancer IMRT, IGRT, SBRT: ADVANCES IN THE TREATMENT PLANNING AND DELIVERY OF RADIOTHERAPY Chang, S. T., Goodman, K. A., Yang, G. R., Koong, A. C. 2007; 40: 386-394

    Abstract

    Pancreatic cancer is a devastating disease with few effective treatment modalities. Recent technological advances have made possible the delivery of single-fraction stereotactic body radiotherapy (SBRT) to patients with locally advanced pancreatic tumors. This paper presents experience at Stanford University with SBRT for patients with unresectable pancreatic cancer. Pancreatic tumors of up to 100 cm3 could be treated. Patients achieved greater than 90% local control for the remainder of their lives. Currently, the standard dose for pancreatic tumors treated at this institution is 25 Gy given in a single fraction. Four-dimensional CT and PET scans have been essential for optimal treatment planning. PET-CT scanning may be a more effective method for evaluating tumor response than conventional CT scanning. Adjuvant systemic therapies could be administered in coordination with SBRT. SBRT is an effective method of treating patients resulting in excellent local control. Current research is aimed at defining the optimal method of combining this treatment with other cancer therapies.

    View details for Web of Science ID 000248596600023

    View details for PubMedID 17641521

  • Plasma osteopontin is an independent prognostic marker for head and neck cancers JOURNAL OF CLINICAL ONCOLOGY Petrik, D., Lavori, P. W., Cao, H., Zhu, Y., Wong, P., Christofferson, E., Kaplan, M. J., Pinto, H. A., Sutphin, P., Koong, A. C., Giaccia, A. J., Le, Q. 2006; 24 (33): 5291-5297

    Abstract

    To confirm the relationship between plasma osteopontin (OPN) levels and treatment outcomes in head and neck squamous cell carcinoma (HNSCC) patients in an expanded study.One hundred forty patients with newly diagnosed HNSCC were enrolled onto this study, 54 previously reported and 86 new patients. Pretreatment plasma OPN levels were assessed in all patients by an enzyme-linked immunosorbent assay method. OPN levels were correlated to treatment outcomes in the new group of patients. Detailed analyses were also performed on the relationship between OPN and tumor control rate, event-free survival (EFS), and postrelapse survival for the entire group.Using a previously defined cut off point of 450 ng/mL, there was a significant correlation between OPN and freedom-from-relapse (P = .047), overall survival (P = .019), and EFS (P = .023) in the new, independent patient cohort (n = 86). Sequence of event analyses using the entire group (N = 140) revealed that OPN was an independent prognostic factor for initial tumor control, EFS in those who have achieved tumor control, and postrelapse survival.In this expanded study, we were able to replicate the prognostic significance of OPN using a predefined cut off point in an independent patient group and demonstrated that plasma OPN is an independent prognostic marker for HNSCC.

    View details for DOI 10.1200/JCO.2006.06.8627

    View details for Web of Science ID 000242342800017

    View details for PubMedID 17114663

  • Results of a phase I dose-escalation study using single-fraction stereotactic radiotherapy for lung tumors JOURNAL OF THORACIC ONCOLOGY Le, Q., Loo, B. W., Ho, A., Cotrutz, C., Koong, A. C., Wakelee, H., Kee, S. T., Constantinescu, D., Whyte, R. I., Donington, J. 2006; 1 (8): 802-809

    Abstract

    The purpose of this study was to report initial results of a phase I study using single-fraction stereotactic radiotherapy (RT) in patients with inoperable lung tumors.Eligible patients included those with inoperable T1-2N0 non-small cell lung cancer (NSCLC) or solitary lung metastases. Treatments were delivered by means of the CyberKnife. All patients underwent computed tomography-guided metallic fiducial placement in the tumor for image-guided targeting. Nine to 20 patients were treated per dose cohort starting at 15 Gy/fraction followed by dose escalation of 5 to 10 Gy to a maximal dose of 30 Gy/fraction. A minimal 3-month period was required between each dose level to monitor toxicity.Thirty-two patients (21 NSCLC and 11 metastatic tumors) were enrolled. At 25 Gy, pulmonary toxicity was noted in patients with prior pulmonary RT and treatment volumes greater than 50 cc; therefore, dose escalation to 30 Gy was applied only to unirradiated patients and treatment volume less than 50 cc. Ten patients received doses less than 20 Gy, 20 received 25 Gy, and two received 30 Gy. RT-related complications were noted for doses greater than 25 Gy and included four cases of grade 2 to 3 pneumonitis, one pleural effusion, and three possible treatment-related deaths. The 1-year freedom from local progression was 91% for dose greater than 20 Gy and 54% for dose less than 20 Gy in NSCLC (p = 0.03). NSCLC patients had significantly better freedom from relapse (p = 0.003) and borderline higher survival than those with metastatic tumors (p = 0.07).Single-fraction stereotactic RT is feasible for selected patients with lung tumors. For those with prior thoracic RT, 25 Gy may be too toxic. Higher dose was associated with improved local control. Longer follow-up is necessary to determine the treatment efficacy and toxicity.

    View details for Web of Science ID 000241649300008

    View details for PubMedID 17409963

  • Four-dimensional cone-beam computed tomography using an on-board imager MEDICAL PHYSICS Li, T., Xing, L., Munro, P., McGuinness, C., Chao, M., Yang, Y., Loo, B., Koong, A. 2006; 33 (10): 3825-3833

    Abstract

    On-board cone-beam computed tomography (CBCT) has recently become available to provide volumetric information of a patient in the treatment position, and holds promises for improved target localization and irradiation dose verification. The design of currently available on-board CBCT, however, is far from optimal. Its quality is adversely influenced by many factors, such as scatter, beam hardening, and intra-scanning organ motion. In this work we quantitatively study the influence of organ motion on CBCT imaging and investigate a strategy to acquire high quality phase-resolved [four-dimensional (4D)] CBCT images based on phase binning of the CBCT projection data. An efficient and robust method for binning CBCT data according to the patient's respiratory phase derived in the projection space was developed. The phase-binned projections were reconstructed using the conventional Feldkamp algorithm to yield 4D CBCT images. Both phantom and patient studies were carried out to validate the technique and to optimize the 4D CBCT data acquisition protocol. Several factors that are important to the clinical implementation of the technique, such as the image quality, scanning time, number of projections, and radiation dose, were analyzed for various scanning schemes. The general references drawn from this study are: (i) reliable phase binning of CBCT projections is accomplishable with the aid of external or internal marker and simple analysis of its trace in the projection space, and (ii) artifact-free 4D CBCT images can be obtained without increasing the patient radiation dose as compared to the current 3D CBCT scan.

    View details for DOI 10.1118/1.2349692

    View details for Web of Science ID 000241424100024

    View details for PubMedID 17089847

  • Reducing respiratory motion artifacts in positron emission tomography through retrospective stacking MEDICAL PHYSICS Thorndyke, B., Schreibmann, E., Koong, A., Xing, L. 2006; 33 (7): 2632-2641

    Abstract

    Respiratory motion artifacts in positron emission tomography (PET) imaging can alter lesion intensity profiles, and result in substantially reduced activity and contrast-to-noise ratios (CNRs). We propose a corrective algorithm, coined "retrospective stacking" (RS), to restore image quality without requiring additional scan time. Retrospective stacking uses b-spline deformable image registration to combine amplitude-binned PET data along the entire respiratory cycle into a single respiratory end point. We applied the method to a phantom model consisting of a small, hot vial oscillating within a warm background, as well as to 18FDG-PET images of a pancreatic and a liver patient. Comparisons were made using cross-section visualizations, activity profiles, and CNRs within the region of interest. Retrospective stacking was found to properly restore the lesion location and intensity profile in all cases. In addition, RS provided CNR improvements up to three-fold over gated images, and up to five-fold over ungated data. These phantom and patient studies demonstrate that RS can correct for lesion motion and deformation, while substantially improving tumor visibility and background noise.

    View details for DOI 10.1118/1.2207367

    View details for Web of Science ID 000239173900035

    View details for PubMedID 16898467

  • Targeting XBP-1 as a novel anti-cancer strategy CANCER BIOLOGY & THERAPY Koong, A. C., Chauhan, V., Romero-Ramirez, L. 2006; 5 (7): 756-759

    Abstract

    The survival and growth of tumor cells within the microenvironment of a solid tumor necessitates the adaptation of these cells to ER stress. Hypoxia, in the context of the tumor microenvironment, is a critical ER stress that activates the unfolded protein response (UPR). This review focuses on the role of the IRE1-XBP1 branch of the UPR and its role in mediating cell survival and tumor growth. Inhibition of this pathway will be discussed as a therapeutic strategy.

    View details for Web of Science ID 000240705300017

    View details for PubMedID 16861911

  • Overview of image-guided radiation therapy MEDICAL DOSIMETRY Xing, L., Thorndyke, B., Schreibmann, E., Yang, Y., Li, T., Kim, G., Luxton, G., Koong, A. 2006; 31 (2): 91-112

    Abstract

    Radiation therapy has gone through a series of revolutions in the last few decades and it is now possible to produce highly conformal radiation dose distribution by using techniques such as intensity-modulated radiation therapy (IMRT). The improved dose conformity and steep dose gradients have necessitated enhanced patient localization and beam targeting techniques for radiotherapy treatments. Components affecting the reproducibility of target position during and between subsequent fractions of radiation therapy include the displacement of internal organs between fractions and internal organ motion within a fraction. Image-guided radiation therapy (IGRT) uses advanced imaging technology to better define the tumor target and is the key to reducing and ultimately eliminating the uncertainties. The purpose of this article is to summarize recent advancements in IGRT and discussed various practical issues related to the implementation of the new imaging techniques available to radiation oncology community. We introduce various new IGRT concepts and approaches, and hope to provide the reader with a comprehensive understanding of the emerging clinical IGRT technologies. Some important research topics will also be addressed.

    View details for DOI 10.1016/j.meddos.2005.12.004

    View details for Web of Science ID 000237818000002

    View details for PubMedID 16690451

  • Mature results from a randomized phase II trial of cisplatin plus 5-fluorouracil and radiotherapy with or without tirapazamine in patients with resectable stage IV head and neck squamous cell carcinomas CANCER Le, Q. T., Taira, A. I., Budenz, S., Dorie, M. J., Goffinet, D. R., Fee, W. E., Goode, R., Bloch, D., Koong, A., Brown, J. M., Pinto, H. A. 2006; 106 (9): 1940-1949

    Abstract

    The objective of this article was to report the results from a randomized trial that evaluated the efficacy and toxicity of adding tirapazamine (TPZ) to chemoradiotherapy in the treatment of patients with head and neck squamous cell carcinomas (HNSCC).Sixty-two patients with lymph node-positive, resectable, TNM Stage IV HNSCC were randomized to receive either 2 cycles of induction chemotherapy (TPZ, cisplatin, and 5-fluorouracil [5-FU]) followed by simultaneous chemoradiotherapy (TPZ, cisplatin, and 5-FU) or to receive the same regimen without TPZ. Patients who did not achieve a complete response at 50 Grays underwent surgical treatment. Stratification factors for randomization included tumor site, TNM stage, and median tumor oxygen tension. The primary endpoint was complete lymph node response.The addition of TPZ resulted in increased hematologic toxicity. There was 1 treatment-related death from induction chemotherapy. The complete clinical and pathologic response rate in the lymph nodes was 90% and 74% for the standard treatment arm and the TPZ arm, respectively (P = .08) and 89% and 90% at the primary site in the respective treatment arms (P = .71). The 5-year overall survival rate was 59%, the cause-specific survival rate was 68%, the rate of freedom from recurrence was 69%, and the locoregional control rate was 77% for the entire group. There was no difference with regard to any of the outcome parameters between the 2 treatment arms. The significant long-term toxicity rate also was found to be similar between the 2 arms.The addition of TPZ increased hematologic toxicity but did not improve outcomes in patients with resectable, Stage IV HNSCC using the protocol administered this small randomized study. The combination of induction and simultaneous chemoradiotherapy resulted in excellent survival in these patients.

    View details for DOI 10.1002/cncr.21785

    View details for Web of Science ID 000237187400010

    View details for PubMedID 16532436

  • An evaluation of tumor oxygenation and gene expression in patients with early stage non-small cell lung cancers CLINICAL CANCER RESEARCH Le, Q. T., Chen, E., Salim, A., Cao, H. B., Kong, C. S., Whyte, R., Donington, J., Cannon, W., Wakelee, H., Tibshirani, R., Mitchell, J. D., Richardson, D., O'Byrne, K. J., Koong, A. C., Giaccia, A. J. 2006; 12 (5): 1507-1514

    Abstract

    To directly assess tumor oxygenation in resectable non-small cell lung cancers (NSCLC) and to correlate tumor pO2 and the selected gene and protein expression to treatment outcomes.Twenty patients with resectable NSCLC were enrolled. Intraoperative measurements of normal lung and tumor pO2 were done with the Eppendorf polarographic electrode. All patients had plasma osteopontin measurements by ELISA. Carbonic anhydrase-IX (CA IX) staining of tumor sections was done in the majority of patients (n = 16), as was gene expression profiling (n = 12) using cDNA microarrays. Tumor pO2 was correlated with CA IX staining, osteopontin levels, and treatment outcomes.The median tumor pO2 ranged from 0.7 to 46 mm Hg (median, 16.6) and was lower than normal lung pO2 in all but one patient. Because both variables were affected by the completeness of lung deflation during measurement, we used the ratio of tumor/normal lung (T/L) pO2 as a reflection of tumor oxygenation. The median T/L pO2 was 0.13. T/L pO2 correlated significantly with plasma osteopontin levels (r = 0.53, P = 0.02) and CA IX expression (P = 0.006). Gene expression profiling showed that high CD44 expression was a predictor for relapse, which was confirmed by tissue staining of CD44 variant 6 protein. Other variables associated with the risk of relapse were T stage (P = 0.02), T/L pO2 (P = 0.04), and osteopontin levels (P = 0.001).Tumor hypoxia exists in resectable NSCLC and is associated with elevated expression of osteopontin and CA IX. Tumor hypoxia and elevated osteopontin levels and CD44 expression correlated with poor prognosis. A larger study is needed to confirm the prognostic significance of these factors.

    View details for DOI 10.1158/1078-0432.CCR-05-2049

    View details for Web of Science ID 000235988000016

    View details for PubMedID 16533775

  • Identification of mitogen-activated protein kinase signaling pathways that confer resistance to endoplasmic reticulum stress in Saccharomyces cerevisiae MOLECULAR CANCER RESEARCH Chen, Y. J., Feldman, D. E., Deng, C. C., BROWN, J. A., De Giacomo, A. F., Gaw, A. F., Shi, G. Y., Le, Q. T., Brown, J. M., Koong, A. C. 2005; 3 (12): 669-677

    Abstract

    Hypoxia activates all components of the unfolded protein response (UPR), a stress response initiated by the accumulation of unfolded proteins within the endoplasmic reticulum (ER). Our group and others have shown previously that the UPR, a hypoxia-inducible factor-independent signaling pathway, mediates cell survival during hypoxia and is required for tumor growth. Identifying new genes and pathways that are important for survival during ER stress may lead to the discovery of new targets in cancer therapy. Using the set of 4,728 homozygous diploid deletion mutants in budding yeast, Saccharomyces cerevisiae, we did a functional screen for genes that conferred resistance to ER stress-inducing agents. Deletion mutants in 56 genes showed increased sensitivity under ER stress conditions. Besides the classic UPR pathway and genes related to calcium homeostasis, we report that two additional pathways, including the SLT2 mitogen-activated protein kinase (MAPK) pathway and the osmosensing MAPK pathway, were also required for survival during ER stress. We further show that the SLT2 MAPK pathway was activated during ER stress, was responsible for increased resistance to ER stress, and functioned independently of the classic IRE1/HAC1 pathway. We propose that the SLT2 MAPK pathway is an important cell survival signaling pathway during ER stress. This study shows the feasibility of using the yeast deletion pool to identify relevant mammalian orthologues of the UPR.

    View details for DOI 10.1158/1541-7786.MCR-05-0181

    View details for Web of Science ID 000234499800003

    View details for PubMedID 16380504

  • Radiation dose reduction in four-dimensional computed tomography MEDICAL PHYSICS Li, T., Schreibmann, E., Thorndyke, B., Tillman, G., Boyer, A., Koong, A., Goodman, K., Xing, L. 2005; 32 (12): 3650-3660

    Abstract

    Four-dimensional (4D) CT is useful in many clinical situations, where detailed abdominal and thoracic imaging is needed over the course of the respiratory cycle. However, it usually delivers a larger radiation dose than the standard three-dimensional (3D) CT, since multiple scans at each couch position are required in order to provide the temporal information. Our purpose in this work is to develop a method to perform 4D CT scans at relatively low current, hence reducing the radiation exposure of the patients. To deal with the increased statistical noise caused by the low current, we proposed a novel 4D penalized weighted least square (4D-PWLS) smoothing method, which can incorporate both spatial and phase information. The 4D images at different phases were registered to the same phase via a deformable model, thereby, a regularization term combining temporal and spatial neighbors can be designed for the 4D-PWLS objective function. The proposed method was tested with phantom experiments and a patient study, and superior noise suppression and resolution preservation were observed. A quantitative evaluation of the benefit of the proposed method to 4D radiotherapy and 4D PET/CT imaging are under investigation.

    View details for DOI 10.1118/1.2122567

    View details for Web of Science ID 000234643700016

    View details for PubMedID 16475764

  • Phase II study to assess the efficacy of conventionally fractionated radiotherapy followed by a stereotactic radiosurgery boost in patients with locally advanced pancreatic cancer INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Koong, A. C., Christofferson, E., Le, Q. T., Goodman, K. A., Ho, A., Kuo, T., Ford, J. M., Fisher, G. A., Greco, R., Norton, J., Yang, G. P. 2005; 63 (2): 320-323

    Abstract

    To determine the efficacy of concurrent 5-fluorouracil (5-FU) and intensity-modulated radiotherapy (IMRT) followed by body stereotactic radiosurgery (SRS) in patients with locally advanced pancreatic cancer.In this prospective study, all patients (19) had pathologically confirmed adenocarcinoma and were uniformly staged. Our treatment protocol consisted of 45 Gy IMRT with concurrent 5-FU followed by a 25 Gy SRS boost to the primary tumor.Sixteen patients completed the planned therapy. Two patients experienced Grade 3 toxicity (none had more than Grade 3 toxicity). Fifteen of these 16 patients were free from local progression until death. Median overall survival was 33 weeks.Concurrent IMRT and 5-FU followed by SRS in patients with locally advanced pancreatic cancer results in excellent local control, but does not improve overall survival and is associated with more toxicity than SRS, alone.

    View details for DOI 10.1016/j.ijrobp.2005.07.002

    View details for Web of Science ID 000232083700002

    View details for PubMedID 16168826

  • Hypoxia upregulates osteopontin expression in NIH-3T3 cells via a ras-activated enhancer ONCOGENE Zhu, Y. H., Denhardt, D. T., Cao, H. B., Sutphin, P. D., Koong, A. C., Giaccia, A. J., Le, Q. T. 2005; 24 (43): 6555-6563

    Abstract

    Osteopontin (OPN) is a secreted phosphoglycoprotein that has been linked to tumor progression and survival in several solid tumors, including head and neck cancers. Previous studies showed that OPN expression is induced by tumor hypoxia, and its plasma levels can serve as a surrogate marker for tumor hypoxia and treatment outcome in head and neck cancer patients. In this study, we investigate the transcriptional mechanism by which hypoxia enhances OPN expression. We found that OPN is induced in head and neck squamous cell carcinoma (HNSCC) cell lines and in NIH3T3 cells by hypoxia at both mRNA and protein levels in a time-dependent manner. Actinomycin D chase experiments showed that hypoxic induction of OPN was not due to increased mRNA stability. Deletion analyses of the mouse OPN promoter regions indicated that a ras-activated enhancer (RAE) located at -731 to -712 relative to the transcription start site was essential for hypoxia-enhanced OPN transcription. Using electrophoretic mobility shift assays with the RAE DNA sequence, we found that hypoxia induced sequence-specific DNA-binding complexes. Furthermore, hypoxia and ras exposure resulted in an additive induction of OPN protein and mRNA levels that appeared to be mediated by the RAE. Induction of OPN through the RAE element by hypoxia is mediated by an Akt-kinase signaled pathway as decreasing Akt levels with dominant negative constructs resulted in inhibition of OPN induction by hypoxia. Taken together, these results have identified a new hypoxia responsive transcriptional enhancer that is regulated by Akt signaling.

    View details for DOI 10.1038/sj.onc.1208800

    View details for Web of Science ID 000232204100009

    View details for PubMedID 16007184

  • A noninvasive approach for assessing tumor hypoxia in xenografts: Developing a urinary marker for hypoxia CANCER RESEARCH Nelson, D. W., Cao, H. B., Zhu, Y. H., Sunar-Reeder, B., Choi, C. Y., Faix, J. D., Brown, J. M., Koong, A. C., Giaccia, A. J., Le, Q. T. 2005; 65 (14): 6151-6158

    Abstract

    Tumor hypoxia modifies the efficacy of conventional anticancer therapy and promotes malignant tumor progression. Human chorionic gonadotropin (hCG) is a glycoprotein secreted during pregnancy that has been used to monitor tumor burden in xenografts engineered to express this marker. We adapted this approach to use urinary beta-hCG as a secreted reporter protein for tumor hypoxia. We used a hypoxia-inducible promoter containing five tandem repeats of the hypoxia-response element (HRE) ligated upstream of the beta-hCG gene. This construct was stably integrated into two different cancer cell lines, FaDu, a human head and neck squamous cell carcinoma, and RKO, a human colorectal cancer cell line. In vitro studies showed that tumor cells stably transfected with this plasmid construct secrete beta-hCG in response to hypoxia or hypoxia-inducible factor 1alpha (HIF-1alpha) stabilizing agents. The hypoxia responsiveness of this construct can be blocked by treatment with agents that affect the HIF-1alpha pathways, including topotecan, 1-benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole (YC-1), and flavopiridol. Immunofluorescent analysis of tumor sections and quantitative assessment with flow cytometry indicate colocalization between beta-hCG and 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5) and beta-hCG and pimonidazole, two extrinsic markers for tumor hypoxia. Secretion of beta-hCG from xenografts that contain these stable constructs is directly responsive to changes in tumor oxygenation, including exposure of the animals to 10% O2 and tumor bed irradiation. Similarly, urinary beta-hCG levels decline after treatment with flavopiridol, an inhibitor of HIF-1 transactivation. This effect was observed only in tumor cells expressing a HRE-regulated reporter gene and not in tumor cells expressing a cytomegalovirus-regulated reporter gene. The 5HRE beta-hCG reporter system described here enables serial, noninvasive monitoring of tumor hypoxia in a mouse model by measuring a urinary reporter protein.

    View details for Web of Science ID 000230633400024

    View details for PubMedID 16024616

  • Sample classification from protein mass spectrometry, by 'peak probability contrasts' BIOINFORMATICS Tibshirani, R., Hastie, T., Narasimhan, B., Soltys, S., Shi, G. Y., Koong, A., Le, Q. T. 2004; 20 (17): 3034-3044

    Abstract

    Early cancer detection has always been a major research focus in solid tumor oncology. Early tumor detection can theoretically result in lower stage tumors, more treatable diseases and ultimately higher cure rates with less treatment-related morbidities. Protein mass spectrometry is a potentially powerful tool for early cancer detection. We propose a novel method for sample classification from protein mass spectrometry data. When applied to spectra from both diseased and healthy patients, the 'peak probability contrast' technique provides a list of all common peaks among the spectra, their statistical significance and their relative importance in discriminating between the two groups. We illustrate the method on matrix-assisted laser desorption and ionization mass spectrometry data from a study of ovarian cancers.Compared to other statistical approaches for class prediction, the peak probability contrast method performs as well or better than several methods that require the full spectra, rather than just labelled peaks. It is also much more interpretable biologically. The peak probability contrast method is a potentially useful tool for sample classification from protein mass spectrometry data.

    View details for DOI 10.1093/bioinformatics/bth357

    View details for Web of Science ID 000225361400017

    View details for PubMedID 15226172

  • Phase II double-blind randomized study comparing oral aloe vera versus placebo to prevent radiation-related mucositis in patients with head-and-neck neoplasms INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Su, C. K., Mehta, V., Ravikumar, L., Shah, R., PINTO, H., Halpern, J., Koong, A., Goffinet, D., Le, Q. T. 2004; 60 (1): 171-177

    Abstract

    In a single-institution, double-blind, prospective, randomized trial, we determined whether oral aloe vera gel can reduce radiation-induced mucositis in head-and-neck cancer patients.We randomized 58 head-and-neck cancer patients between oral aloe vera and placebo. To be included in this Phase II protocol, patients had to be treated with radiotherapy with curative intent at Stanford University between February 1999 and March 2002. We examined patients biweekly for mucositis at 15 head-and-neck subsites and administered quality-of-life questionnaires.Patients in the aloe and placebo groups were statistically identical in baseline characteristics. By the end of treatment, the two groups were also statistically identical in maximal grade of toxicity, duration of Grade 2 or worse mucositis, quality-of-life scores, percentage of weight loss, use of pain medications, hydration requirement, oral infections, and prolonged radiation breaks.In our randomized study, oral aloe vera was not a beneficial adjunct to head-and-neck radiotherapy. The mean quality-of-life scores were greater in the aloe vera group, but the differences were not statistically significant. Oral aloe vera did not improve tolerance to head-and-neck radiotherapy, decrease mucositis, reduce soreness, or otherwise improve patient well-being.

    View details for DOI 10.1016/j.ijrobp.2004.02.012

    View details for Web of Science ID 000223854500022

    View details for PubMedID 15337553

  • The use of plasma surface-enhanced laser desorption/ionization time-of-flight mass spectrometry proteomic patterns for detection of head and neck squamous cell cancers CLINICAL CANCER RESEARCH Soltys, S. G., Le, Q. T., Shi, G. Y., Tibshirani, R., Giaccia, A. J., Koong, A. C. 2004; 10 (14): 4806-4812

    Abstract

    Our study was undertaken to determine the utility of plasma proteomic profiling using surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry for the detection of head and neck squamous cell carcinomas (HNSCCs).Pretreatment plasma samples from HNSCC patients or controls without known neoplastic disease were analyzed on the Protein Biology System IIc SELDI-TOF mass spectrometer (Ciphergen Biosystems, Fremont, CA). Proteomic spectra of mass:charge ratio (m/z) were generated by the application of plasma to immobilized metal-affinity-capture (IMAC) ProteinChip arrays activated with copper. A total of 37356 data points were generated for each sample. A training set of spectra from 56 cancer patients and 52 controls were applied to the "Lasso" technique to identify protein profiles that can distinguish cancer from noncancer, and cross-validation was used to determine test errors in this training set. The discovery pattern was then used to classify a separate masked test set of 57 cancer and 52 controls. In total, we analyzed the proteomic spectra of 113 cancer patients and 104 controls.The Lasso approach identified 65 significant data points for the discrimination of normal from cancer profiles. The discriminatory pattern correctly identified 39 of 57 HNSCC patients and 40 of 52 noncancer controls in the masked test set. These results yielded a sensitivity of 68% and specificity of 73%. Subgroup analyses in the test set of four different demographic factors (age, gender, and cigarette and alcohol use) that can potentially confound the interpretation of the results suggest that this model tended to overpredict cancer in control smokers.Plasma proteomic profiling with SELDI-TOF mass spectrometry provides moderate sensitivity and specificity in discriminating HNSCC. Further improvement and validation of this approach is needed to determine its usefulness in screening for this disease.

    View details for Web of Science ID 000222840700027

    View details for PubMedID 15269156

  • Identification of hypoxia regulated proteins in head and neck cancer by proteomic and tissue array profiling. Cancer Res Chen, et al 2004; 64 (20): 7302-10
  • Improved local control with stereotactic radiosurgical boost in patients with nasopharyngeal carcinoma INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Le, Q. T., Tate, D., Koong, A., Gibbs, I. C., Chang, S. D., Adler, J. R., Pinto, H. A., Terris, D. J., Fee, W. E., Goffinet, D. R. 2003; 56 (4): 1046-1054

    Abstract

    Treatment of nasopharyngeal carcinoma using conventional external beam radiotherapy (EBRT) alone is associated with a significant risk of local recurrence. Stereotactic radiosurgery (STR) was used to boost the tumor site after EBRT to improve local control.Forty-five nasopharyngeal carcinoma patients received a STR boost after EBRT at Stanford University. Seven had T1, 16 had T2, 4 had T3, and 18 had T4 tumors (1997 American Joint Commission on Cancer staging). Ten had Stage II, 8 had Stage III, and 27 had Stage IV neoplasms. Most patients received 66 Gy of EBRT delivered at 2 Gy/fraction. Thirty-six received concurrent cisplatin-based chemotherapy. STR was delivered to the primary site 4-6 weeks after EBRT in one fraction of 7-15 Gy.At a medium follow-up of 31 months, no local failures had occurred. The 3-year local control rate was 100%, the freedom from distant metastasis rate was 69%, the progression-free survival rate was 71%, and the overall survival rate was 75%. Univariate and multivariate analyses revealed N stage (favoring N0-N1, p = 0.02, hazard ratio HR 4.2) and World Health Organization histologic type (favoring type III, p = 0.002, HR 13) as significant factors for freedom from distant metastasis. World Health Organization histologic type (p = 0.004, HR 10.5) and age (p = 0.01, HR 1.07/y) were significant factors for survival. Late toxicity included transient cranial nerve weakness in 4, radiation-related retinopathy in 1, and asymptomatic temporal lobe necrosis in 3 patients who originally had intracranial tumor extension.STR boost after EBRT provided excellent local control in nasopharyngeal carcinoma patients. The incidence of late toxicity was acceptable. More effective systemic treatment is needed to achieve improved survival.

    View details for DOI 10.1016/S0360-3016(03)00117-2

    View details for Web of Science ID 000183937500018

    View details for PubMedID 12829140

  • Comparison of the comet assay and the oxygen microelectrode for measuring tumor oxygenation in head-and-neck cancer patients INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Le, Q. T., Kovacs, M. S., Dorie, M. J., Koong, A., Terris, D. J., Pinto, H. A., Goffinet, D. R., Nowels, K., Bloch, D., Brown, J. M. 2003; 56 (2): 375-383

    Abstract

    To compare the Eppendorf PO2 histograph and the alkaline comet assay as methods of measuring tumor hypoxia in patients with head-and-neck squamous cell carcinomas.As part of a larger clinical trial, 65 patients with head-and-neck squamous cell carcinoma nodal metastasis underwent tumor oxygenation measurements with Eppendorf PO2 histographs and comet assays, performed on fine-needle aspirates at 1 and 2 min after 5 Gy. Fifty-four patients had sufficient tumor cells for comet analysis at 1 min and 26 at both 1 and 2 min. Individual cells were examined for DNA single-strand breaks by alkaline gel electrophoresis, and the distribution of values was quantified using median tail moment (MTM). Nonirradiated tumor cells from pretreatment fine-needle aspirates received 5 Gy in vitro to establish the oxygenated response.There was a significant correlation between the 1- and 2-min MTM (slope = 0.77 +/- 0.03). There was no relationship between DNA damage in tumor cells irradiated in vitro and in vivo. No correlation was found between Eppendorf PO2 measurements and comet MTM. There was a statistically significant correlation between the treatment response in the node studied and comet MTMs, whereas no correlation was observed between treatment response and Eppendorf measurements.Comet assays are reproducible, as shown by biopsies at 1 and 2 min. Intertumor variation in the MTM is not a result of intrinsic radiosensitivity but of tumor hypoxia. There was no correlation between Eppendorf PO2 measurements and comet MTM. Comet assays were better than Eppendorf in predicting treatment response as an end point for short-term outcome. Longer follow-up is needed to determine the role of the comet assay as a predictor for locoregional tumor control and survivals.

    View details for DOI 10.1016/S0360-3016(02)04503-0

    View details for Web of Science ID 000182861500010

    View details for PubMedID 12738312

  • Phase II trial of preoperative 3D conformal radiotherapy, protracted venous infusion 5-fluorouracil, and weekly CPT-11, followed by surgery for ultrasound-staged T3 rectal cancer INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Mehta, V. K., Cho, C., Ford, J. M., Jambalos, C., Poen, J., Koong, A., Lin, A., Bastidas, J. A., Young, H., Dunphy, E. P., Fisher, G. 2003; 55 (1): 132-137

    Abstract

    CPT-11 sensitizes tumor cells to radiation and in combination therapy with 5-fluorouracil (5-FU) results in enhanced cytotoxicity to metastatic colorectal cancer. We report the results from a Phase II trial of preoperative radiotherapy (RT), CPT-11, and 5-FU for patients with ultrasound-staged T3 rectal cancer.Between April 1999 and August 2001, 32 patients (21 men, 11 women; median age 52 years, range 40-74) with biopsy-proven adenocarcinoma of the rectum were enrolled in the study. All patients underwent endorectal ultrasonography for staging (uT3N0 = 19; uT3N1 = 13; uT2N1 = 1). RT was prescribed to the draining lymph nodes (45 Gy in 1.8-Gy daily fractions) and tumor (50.4 Gy in 1.8-Gy daily fractions). Patients also received concurrent CPT-11 (50 mg/m(2), Days 1, 8, 15, and 22) and 5-FU (200 mg/m(2) daily, 7 d/wk, Days 1-33). Surgical resection was performed 6-10 weeks after completing chemoradiotherapy.Acute toxicity was frequently observed, and 18 patients (56%) required either a chemotherapy dose reduction or RT interruption of >3 days. One patient withdrew because of diarrhea and abdominal cramping (Grade III) after 10 days of treatment. Although no Grade IV toxicity was observed, Grade III diarrhea (n = 9, 28%), mucositis (n = 7, 21%), rectal sores (n = 7, 21%), abdominal cramping (n = 3, 9%) were noted. Of the 32 patients who underwent surgery, 12 had a complete pathologic response. Of the 32 patients, the disease of 23 (71%) was downstaged. The average length of hospitalization was between 5 and 12 days, with 1 patient staying 33 days. All patients were followed for disease-free survival.Although associated with frequent acute toxicity, the regimen is associated with significant tumor "downstaging." Additional patients and longer follow-up are necessary to define the role of this regimen fully.

    View details for Web of Science ID 000181070600018

    View details for PubMedID 12504045

  • Identification of osteopontin as a prognostic plasma marker for head and neck squamous cell carcinomas CLINICAL CANCER RESEARCH Le, Q. T., Sutphin, P. D., Raychaudhuri, S., Yu, S. C., Terris, D. J., Lin, H. S., Lum, B., Pinto, H. A., Koong, A. C., Giaccia, A. J. 2003; 9 (1): 59-67

    Abstract

    Tumor hypoxia modifies treatment efficacy and promotes tumor progression. Here, we investigated the relationship between osteopontin (OPN), tumor pO(2), and prognosis in patients with head and neck squamous cell carcinomas (HNSCC).We performed linear discriminant analysis, a machine learning algorithm, on the NCI-60 cancer cell line microarray expression database to identify a gene profile that best distinguish cell lines with high Von-Hippel Lindau (VHL) gene expression, an important regulator of hypoxia-related genes, from those with low expression. Plasma OPN levels in 15 volunteers, 31 VHL patients, and 54 HNSCC patients were quantitatively measured by ELISA. The relationships between plasma OPN levels, tumor pO(2) as measured by the Eppendorf microelectrode, freedom from relapse (FFR), and survival in HNSCC patients were evaluated.Microarray analysis indicated that OPN gene expression inversely correlated with that of VHL. These findings were confirmed by Northern blot analysis. ELISA studies and Western blot in a HNSCC cell line demonstrated that hypoxia exposure resulted in increased OPN secretion. Patients with VHL syndrome had significantly higher plasma OPN levels than healthy volunteers. Plasma OPN level inversely correlated with tumor pO(2) (P = 0.003, r = -0.42). OPN levels correlated with clinical outcomes. The 1-year FFR and survival rates were 80 and 100%, respectively, for patients with OPN levels 450 ng/ml (P = 0.002 and 0.0005). Multivariate analysis revealed that OPN was an independent predictor for FFR and survival.Plasma OPN levels appeared to correlate with tumor hypoxia in HNSCC patients and may serve as noninvasive tests to identify patients at high risk for tumor recurrence.

    View details for Web of Science ID 000180430600008

    View details for PubMedID 12538452

  • Estimating DNA repair by sequential evaluation of head and neck tumor radiation sensitivity using the comet assay ARCHIVES OF OTOLARYNGOLOGY-HEAD & NECK SURGERY Terris, D. J., Ho, E. Y., Ibrahim, H. Z., Dorie, M. J., Kovacs, M. S., Le, Q. T., Koong, A. C., Pinto, H. A., Brown, J. M. 2002; 128 (6): 698-702

    Abstract

    The alkaline comet assay is a microelectrophoretic technique for detecting single-strand DNA breaks, and may be used as an indirect measure of hypoxia by determining the radiation sensitivity of individual cells.To assess the ability of the comet assay to estimate the rate of DNA repair after irradiation in patients with head and neck cancer.The comet assay was used to evaluate DNA damage in fine-needle aspirates of lymph nodes containing metastatic squamous cell carcinoma in patients with head and neck cancer 1, 2, and 3 minutes after treatment with 500 rad (5 Gy) of irradiation. The amount of DNA damage (measured as the "tail moment" of the comet) is proportional to the number of DNA single-strand breaks after irradiation, which in turn depends on the oxygen concentration in each cell.The mean +/- SD of the median tail moment of the 1-minute postirradiation comets was 29.4 +/- 14.2 (n = 27). After 2 minutes, the mean median tail moment decreased to 25.4 +/- 13.6 (n = 25), representing a mean decrease of 11.9% in those patients with both 1- and 2-minute comet assays. Assuming a linear rate of repair, this decrease in DNA damage corresponds to a repair half-life of 4.2 minutes. A 3-minute assay was also performed on samples from a smaller number of patients (n = 9), with a mean value not significantly different from that of the 2-minute assay of the samples from this group.The comet assay is a promising tool for evaluating radiation sensitivity in individual cells. The rate of DNA repair early after irradiation is consistent with data in the literature.

    View details for Web of Science ID 000176264300013

    View details for PubMedID 12049567

  • Epigenetic regulation of gene expression in cervical cancer cells by the tumor microenvironment CLINICAL CANCER RESEARCH Denko, N., Schindler, C., Koong, A., Laderoute, K., Green, C., Giaccia, A. 2000; 6 (2): 480-487

    Abstract

    Evidence is accumulating that the adverse tumor microenvironment both modifies the malignant progression of tumor cells and contributes to chemotherapy and radiation resistance. We hypothesized that some of the effects on malignant progression are mediated through the transcriptional regulation of genes responsive to the stresses of the microenvironment, such as low oxygen or low glucose conditions. To determine epigenetic changes in gene expression that were consistent with that hypothesis, we used an in vitro subtractive hybridization method, representational difference analysis, to identify hypoxia-induced cDNAs from cultured human cervical epithelial cells. We identified 12 induced genes: two novel genes (HIG1 and HIG2), three genes known to be hypoxia-inducible (tissue factor, GAPDH, thioredoxin), and seven genes not previously identified as hypoxia-inducible [HNRNP(a1), ribosomal L7, annexin V, lipocortin 2, Ku(70), PRPP synthase, and acetoacetyl-CoA thiolase]. In cultured cells, HIG1 and HIG2 expression is induced by hypoxia and by glucose deprivation, but their expression is not induced by serum deprivation, UV, or ionizing radiation. The putative HIG1 and HIG2 open reading frames are expressed in cells, as confirmed by epitope tagging. In addition, tumor xenografts derived from human cervical cancer cells display increased expression of HIG1 and HIG2 when they are deprived of oxygen. Taken together, these data suggest a coordinated transcriptional response of eukaryotic cells to microenvironmental stresses found in the solid tumor.

    View details for Web of Science ID 000085502600023

    View details for PubMedID 10690527

  • HYPOXIC ACTIVATION OF NUCLEAR FACTOR-KAPPA-B IS MEDIATED BY A RAS AND RAF SIGNALING PATHWAY AND DOES NOT INVOLVE MAP KINASE (ERK1 OR ERK2) CANCER RESEARCH Koong, A. C., CHEN, E. Y., Mivechi, N. F., Denko, N. C., STANNBROOK, P., Giaccia, A. J. 1994; 54 (20): 5273-5279

    Abstract

    We have previously shown that hypoxia causes the activation of nuclear factor-kappa B (NF-kappa B), and the phosphorylation of its inhibitory subunit, I kappa B alpha, on tyrosine residues. With the use of dominant negative mutants of Ha-Ras and Raf-1, we investigated some of the early signaling events leading to the activation of NF-kappa B by hypoxia. Both dominant negative alleles of Ha-Ras and Raf-1 inhibited NF-kappa B induction by hypoxia, suggesting that the hypoxia-induced pathway of NF-kappa B induction is dependent on Ras and Raf-1 kinase activity. Furthermore, although conditions of low oxygen can also activate mitogen-activated protein kinases (ERK1 and ERK2), these kinases do not appear to be involved in regulating NF-kappa B by low oxygen conditions, as dominant negative mutants of mitogen-activated protein kinase do not inhibit NF-kappa B activation by hypoxia. Since Ras and Raf-1 have been previously shown to work downstream from membrane-associated tyrosine kinases such as Src, we determined if the Src membrane-associated kinase was also activated by low oxygen conditions. We detected an increase in Src proto-oncogene activity within 15-30 min of cellular exposure to hypoxia. We postulate that Src activation by hypoxia may be one of the earliest events that precedes Ras activation in the signaling cascade which ultimately leads to the phosphorylation and dissociation of the inhibitory subunit of NF-kappa B, I kappa B alpha.

    View details for Web of Science ID A1994PL55800007

    View details for PubMedID 7923153

  • MODULATION OF POTASSIUM CHANNELS BY PROTEIN-TYROSINE KINASE INHIBITORS JOURNAL OF CELLULAR PHYSIOLOGY Saad, A. H., Kuo, S. S., Koong, A. C., Hahn, G. M., Giaccia, A. J. 1994; 161 (1): 142-148

    Abstract

    Exposure of non-excitatory cells to the tyrosine kinase (PTK) inhibitors, genistein, herbimycin A, and tyrphostin, induced at least two families of K+ currents. The first, a TEA-insensitive slow-inactivating K+ current, is induced within 3 min following treatment with 140 mM genistein or 100 nM herbimycin A. The second current, a TEA-sensitive delayed rectifier, is induced within 30 min following treatment with 50 mM genistein or 10 nM herbimycin A. Currents with similar biophysical and pharmacological characteristics are induced in these cells following exposure to ionizing radiation. The radiation-induced currents are inhibited by pretreatment with the free radical scavenger, N-Acetyl L-Cysteine, or by pretreatment with the protein kinase C inhibitor, staurosporine; those induced by PTK inhibitors are not. The latter, therefore, do not appear to be mediated through free radicals or require serine/threonine phosphorylation for activation. Once the channels are activated by the PTK inhibitors, phosphorylation of the channel at serine/threonine residues results in slower inactivation of the induced current. We propose that protein tyrosine phosphorylation of the K+ channel protein itself or of a factor that interacts with it maintains the K+ channels of non-excitatory cells in a closed state. Following exposure to ionizing radiation, free radical-induced activation of serine/threonine kinase(s) results in phosphorylation of the channel and/or inactivation of a tyrosine kinase that in turn leads to activation of the K+ channels.

    View details for Web of Science ID A1994PK53000016

    View details for PubMedID 7929599

  • ANALYSIS OF HSF-1 PHOSPHORYLATION IN A549 CELLS TREATED WITH A VARIETY OF STRESSES INTERNATIONAL JOURNAL OF HYPERTHERMIA Mivechi, N. F., Koong, A. C., Giaccia, A. J., Hahn, G. M. 1994; 10 (3): 371-379

    Abstract

    In the absence of stress, heat shock transcription factor-1 (HSF-1) exists as a monomer. After the treatment of cells with variety of stresses, HSF-1 forms a trimer and binds to the heat shock element (HSE), a motif consisting of three consecutive NGAAN sequences located in an inverted orientation upstream of the heat shock genes. HSF-1 is then phosphorylated causing transactivation of heat shock mRNAs. Treatment of cells with some of the stresses has been shown to increase HSF binding to HSE without detectably increasing the synthesis of heat shock mRNAs. Here we used antibody specific to HSF-1 to detect its phosphorylation status following exposure of A549, a human lung carcinoma cell line to a variety of stresses in order to correlate HSF-1 phosphorylation with its transactivation ability. Our studies show that HSF-1 is phosphorylated following heat shock (43 degrees C for 1 h), hypoxia (5 h exposure to 0.02% oxygen), 8% ethanol (1 h exposure at 37 degrees C), or 200 microM sodium arsenite (1 h exposure at 37 degrees C). All such stresses have previously been shown to increase the synthesis of heat shock proteins (hsps). However, there are no detectable increases in HSF-1 phosphorylation after the treatment of cells with X-irradiation (2-8 Gy) or 100 microM canavanine, an amino acid analogue (1 h exposure at 37 degrees C). Treatment of cells with X-irradiation increases HSF binding to HSE without increasing the synthesis of hsps, while treatment of cells with canavanine has been shown to increase the synthesis of hsps.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1994NP47600009

    View details for PubMedID 7930803

  • HYPOXIA CAUSES THE ACTIVATION OF NUCLEAR FACTOR KAPPA-B THROUGH THE PHOSPHORYLATION OF I-KAPPA-B-ALPHA ON TYROSINE RESIDUES CANCER RESEARCH Koong, A. C., CHEN, E. Y., Giaccia, A. J. 1994; 54 (6): 1425-1430

    Abstract

    The response of mammalian cells to stress is controlled by transcriptional regulatory proteins such as nuclear factor kappa B (NF-kappa B) to induce a wide variety of early response genes. In this report, we show that exposure of cells to hypoxia (0.02% O2) results in I kappa B alpha degradation, increased NF-kappa B DNA binding activity, and transactivation of a reporter gene construct containing two NF-kappa B DNA binding sites. Pretreatment of cells with protein tyrosine kinase inhibitors and the dominant negative allele of c-Raf-1 (Raf 301) inhibited I kappa B alpha degradation, NF-kappa B binding, and transactivation of kappa B reporter constructs by hypoxia. To demonstrate a direct link between changes in the phosphorylation pattern of I kappa B alpha with NF-kappa B activation, we immunoprecipitated I kappa B alpha after varying times of hypoxic exposure and found that its tyrosine phosphorylation status increased during hypoxic exposure. Inhibition of the transfer of tyrosine phosphoryl groups onto I kappa B alpha prevented I kappa B alpha degradation and NF-kappa B binding. In comparison to other activators of NF-kappa B such as phorbol myristate acetate or tumor necrosis factor, we did not detect changes in the tyrosine phosphorylation status of I kappa B alpha following treatment with either of these agents. These results suggest that tyrosine phosphorylation of I kappa B alpha during hypoxia is an important proximal step which precedes its dissociation and degradation from NF-kappa B.

    View details for Web of Science ID A1994NA88700009

    View details for PubMedID 8137243

  • INCREASED CYTOTOXICITY OF CHRONIC HYPOXIC CELLS BY MOLECULAR INHIBITION OF GRP78 INDUCTION INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Koong, A. C., CHEN, E. Y., Lee, A. S., Brown, J. M., Giaccia, A. J. 1994; 28 (3): 661-666

    Abstract

    To develop a molecular strategy of increasing cytotoxicity of chronically hypoxic cells by inhibiting Glucose Regulated Protein 78 kDal (GRP78) induction.A mutant nonGRP78 inducing cell line (78WO) was developed from its parent (DG44) by overexpressing antisense GRP78 mRNA. Following exposure to varying durations of hypoxia, Northern and Western blot analysis were used to characterize the amount of GRP78 expression both at the RNA and protein level. Hypoxia was achieved by placing cells in specially designed hypoxic chambers which were subjected to successive rounds of evacuation and flushing with 95% CO2/N2 to reduce the oxygen in the environment to 0.02% oxygen. After treatment with hypoxia, cells were assayed for colony forming ability.GRP78 mRNA and protein induction following exposure to hypoxia was 3-4 fold lower in the 78WO cell line than in the parental DG44 cell line. Furthermore, it was observed that there was no difference in the cytotoxicity of 78WO and DG44 cells after 10 h of hypoxia. However, after 15 h of hypoxia, the survival of 78WO cells decreased by 1 log and after 20 h of hypoxia, the survival of 78WO decreased by another log.These results show that stress protein induction is important for cellular survival to chronic hypoxia and that inhibition of GRP78 induction may represent a novel therapeutic strategy by selectively sensitizing chronically hypoxic cells within solid tumors.

    View details for Web of Science ID A1994NA83600012

    View details for PubMedID 8113109

  • ACTIVATION OF POTASSIUM CHANNELS BY HYPOXIA AND REOXYGENATION IN THE HUMAN LUNG ADENOCARCINOMA CELL-LINE A549 JOURNAL OF CELLULAR PHYSIOLOGY Koong, A. C., Giaccia, A. J., Hahn, G. M., Saad, A. H. 1993; 156 (2): 341-347

    Abstract

    Active oxygen species are generated in cells during pathophysiologic conditions such as inflammation and postischemic reperfusion. If oxygen radical scavengers are added before reperfusion, then the magnitude of injury is reduced. We investigated whether free radicals generated following exposure to hypoxia and reoxygenation activate voltage-dependent K+ ion channels in tumor cells in vitro. Using the technique of whole cell voltage clamping, we recorded currents from two families of potassium (K+) channels that were activated following reoxygenation. One of these groups possessed the electrophysical characteristics of a tetraethylammonium (TEA)-sensitive delayed rectifier channel and the other possessed characteristics of a Tea-insensitive slow inactivating channel. We present evidence which suggests that K+ channels are activated following reoxygenation but not during the hypoxia phase. The K+ currents decayed with time following reoxygenation. The decay characteristics of the K+ currents depended on the duration and level of hypoxia to which the cells were exposed. To determine whether activation of K+ channels by reoxygenation was initiated by free radicals, we pretreated cells with N-Acetyl L-Cysteine (NAC), a free radical scavenger, and found that this pretreatment abolished the currents induced by reoxygenation. We also present evidence that free radicals do not directly act on the channel itself, but activate a protein kinase which, in turn, activates the K+ channels. Taken together, these results indicate that one of the early responses to oxidative stress is the activation of K+ currents.

    View details for Web of Science ID A1993LP82200016

    View details for PubMedID 8344990

  • POTASSIUM-CHANNEL ACTIVATION IN RESPONSE TO LOW-DOSES OF GAMMA-IRRADIATION INVOLVES REACTIVE OXYGEN INTERMEDIATES IN NONEXCITATORY CELLS PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Kuo, S. S., Saad, A. H., Koong, A. C., Hahn, G. M., Giaccia, A. J. 1993; 90 (3): 908-912

    Abstract

    Active oxygen species are generated during pathophysiologic conditions such as inflammation and ionizing radiation exposure. We tested the hypothesis that an early cellular event in response to these species involves regulation of ion channels. We exposed cells to gamma-irradiation or treated them with hydrogen peroxide, xanthine/xanthine oxidase, or [3H]thymidine and then monitored channel activity by the technique of whole-cell voltage clamping. Recordings showed that both normal and tumor cells exhibit an increase in K+ currents after treatment with radiation, H2O2, and xanthine/xanthine oxidase but not with high specific activity [3H]thymidine, suggesting that the signal for K+ channel activation originates at the cell membrane. A single noncytotoxic dose of 10 cGy induced measurable levels of K+ currents, suggesting that the induction of currents regulates biochemical changes in response to stress. To test whether channel activity is sensitive to active oxygen species, we pretreated cells with N-acetyl-L-cysteine (NAC) to increase cellular pools of free radical scavengers before radiation. In NAC-pretreated cells, K+ channel activation by gamma-irradiation was abolished. It has previously been shown that protein kinase C (PKC) is activated by ionizing radiation and can regulate K+ channels in some cells. However, the effect of radiation on induction of K+ channel activity was independent of PKC, since cells chronically exposed to phorbol esters still produced K+ currents after radiation. These results suggest that an early cellular response to oxidative stress is the activation of K+ channels.

    View details for Web of Science ID A1993KK81300028

    View details for PubMedID 8430104

  • ACTIVATION OF THE HEAT-SHOCK TRANSCRIPTION FACTOR BY HYPOXIA IN NORMAL AND TUMOR-CELL LINES INVIVO AND INVITRO INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Giaccia, A. J., AUGER, E. A., Koong, A., Terris, D. J., Minchinton, A. I., Hahn, G. M., Brown, J. M. 1992; 23 (4): 891-897

    Abstract

    Cells exposed to hypoxia increase their synthesis of a specific set of proteins called oxygen regulated proteins. Recently, three of these proteins have been identified as hemoxygenase, Glucose Regulated Protein 78 kilodaltons and Glucose Regulated Protein 94 kilodaltons. In contrast, reoxygenation from hypoxic conditions increases the synthesis of the heat shock proteins. Although the molecular signals required for regulation of both sets of proteins by hypoxia and reoxygenation are still under investigation, it is known that their expression is regulated at the transcriptional level. This finding suggests that these stresses work either singularly or together to control the activation of nuclear transcription factors which bind distinct regulatory sequences in the promoter region of these genes. One possible nuclear transcription factor which could act as a transcriptional regulator for both hypoxia and reoxygenation gene transcription is the heat shock transcription factor. In this report, we focused on the kinetics of HSF activation by hypoxia in normal and tumor cell lines of murine and human origins. In cell culture, both the normal diploid cell line AG1522 and the tumor cell line JSQ-3 possess the same kinetics of HSF activation (binding to the heat shock element) by hypoxia, with maximal induction at or after 3 hr. We have also shown that the activation of HSF occurs in the SCCVII tumor in vivo without clamping, but not in SCCVII cells grown in monolayers. When SCCVII tumors are dissociated and allowed to reoxygenate in cell culture, HSF binding decreased in 5 hr, and was undetectable after 18 hr. Furthermore, one human tumor biopsy tested for the presence of hypoxia by both the pO2 histograph (Eppendorf, Germany) and HSF binding showed good agreement for both techniques. These results suggest that HSF binding may be a useful marker for monitoring the tumor hypoxia.

    View details for Web of Science ID A1992JD82800027

    View details for PubMedID 1618682

  • THE INFLUENCE OF CHRONIC ANEMIA ON THE RADIOSENSITIVITY OF 2 MOUSE-TUMORS BRITISH JOURNAL OF CANCER Koong, A. C., Hirst, D. G. 1991; 63 (4): 499-502

    Abstract

    There is clear clinical evidence that tumours in anaemic patients are difficult to control with radiotherapy. We have studied the radiosensitivity of two transplantable mouse tumours, the SCCVII/St carcinoma and the KHT sarcoma in hosts made anaemic either with an iron poor diet or as a result of tumour growth. The haemoglobin level and haematocrits of mice on the low iron diet fell to about 60% of normal within 11 weeks. The number of clonogenic cells after a single X-ray dose of 20 Gy was slightly lower (P less than 0.05) in the anaemic animals (2.3 X 10(4) g-1) than in controls (5.2 X 10(4) g-1) though there was no significant difference in the surviving fractions. Mice bearing KHT tumours became anaemic with haematocrits falling to 65% of normal as their tumours grew from 300-1200 mg. A second 'test' tumour was implanted one week after the first 'anaemia-inducing' tumour so that estimates of radiosensitivity could all be carried out on tumours within the same size range (150-300 mg). Radiosensitivity was significantly greater in the most anaemic hosts with 2.2 X 10(4) cells g-1 surviving a dose of 20 Gy compared with 6.7 x 10(4) g-1 in controls (P less than 0.01). These results are consistent with most published data for mouse tumours though not for many human tumours.

    View details for Web of Science ID A1991FH59600007

    View details for PubMedID 2021532

  • THERAPEUTIC ADVANTAGE OF HYPOXIC CELLS IN TUMORS - A THEORETICAL-STUDY JOURNAL OF THE NATIONAL CANCER INSTITUTE Brown, J. M., Koong, A. 1991; 83 (3): 178-185

    Abstract

    The presence of hypoxic cells in solid tumors has long been considered a problem in cancer treatment, particularly for radiation therapy but also for treatment with some anticancer drugs. Three general strategies are being actively explored to overcome the problem: oxygenating the tumor, sensitizing the hypoxic cells to radiation (or chemotherapy), or killing the hypoxic cells (with a hypoxic cell cytotoxin). In the present study, we have examined the impact of each of these three strategies on a standard radiation therapy regimen (30 doses of 2 Gy), using either of two major assumptions: full reoxygenation or no reoxygenation of the tumor cells. We demonstrate that a hypoxic cell cytotoxin can produce a level of tumor cell killing higher (by several orders of magnitude) than that produced by full oxygenation of a tumor or by use of an optimum hypoxic cell radiosensitizer, provided the cytotoxin kills more than approximately 50% of the hypoxic cells each time it is given. The only assumption that makes a difference is whether reoxygenation occurs: In the worst case (ie, no reoxygenation), the hypoxic cell cytotoxin performs only as well as an optimum radiosensitizer. The analysis shows that hypoxic cells in tumors can be a major therapeutic advantage. Therefore, we recommend that research efforts be concentrated on development of superior hypoxic cell cytotoxins rather than improved hypoxic cell radiosensitizers and that, in parallel, emphasis be placed on development of agents to increase hypoxia.

    View details for Web of Science ID A1991EW64900008

    View details for PubMedID 1988703

Conference Proceedings


  • Normal Tissue Complication Probability Modeling of Acute Hematologic Toxicity in Patients Treated With Intensity-Modulated Radiation Therapy for Squamous Cell Carcinoma of the Anal Canal Bazan, J. G., Luxton, G., Mok, E. C., Koong, A. C., Chang, D. T. ELSEVIER SCIENCE INC. 2012: 700-706

    Abstract

    To identify dosimetric parameters that correlate with acute hematologic toxicity (HT) in patients with squamous cell carcinoma of the anal canal treated with definitive chemoradiotherapy (CRT).We analyzed 33 patients receiving CRT. Pelvic bone (PBM) was contoured for each patient and divided into subsites: ilium, lower pelvis (LP), and lumbosacral spine (LSS). The volume of each region receiving at least 5, 10, 15, 20, 30, and 40 Gy was calculated. Endpoints included grade ?3 HT (HT3+) and hematologic event (HE), defined as any grade ?2 HT with a modification in chemotherapy dose. Normal tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Logistic regression was used to test associations between HT and dosimetric/clinical parameters.Nine patients experienced HT3+ and 15 patients experienced HE. Constrained optimization of the LKB model for HT3+ yielded the parameters m = 0.175, n = 1, and TD(50) = 32 Gy. With this model, mean PBM doses of 25 Gy, 27.5 Gy, and 31 Gy result in a 10%, 20%, and 40% risk of HT3+, respectively. Compared with patients with mean PBM dose of <30 Gy, patients with mean PBM dose ?30 Gy had a 14-fold increase in the odds of developing HT3+ (p = 0.005). Several low-dose radiation parameters (i.e., PBM-V10) were associated with the development of HT3+ and HE. No association was found with the ilium, LP, or clinical factors.LKB modeling confirms the expectation that PBM acts like a parallel organ, implying that the mean dose to the organ is a useful predictor for toxicity. Low-dose radiation to the PBM was also associated with clinically significant HT. Keeping the mean PBM dose <22.5 Gy and <25 Gy is associated with a 5% and 10% risk of HT, respectively.

    View details for DOI 10.1016/j.ijrobp.2011.12.072

    View details for Web of Science ID 000309560600053

    View details for PubMedID 22414279

  • Postchemoradiotherapy Positron Emission Tomography Predicts Pathologic Response and Survival in Patients With Esophageal Cancer Jayachandran, P., Pai, R. K., Quon, A., Graves, E., Krakow, T. E., La, T., Loo, B. W., Koong, A. C., Chang, D. T. ELSEVIER SCIENCE INC. 2012: 471-477

    Abstract

    To correlate the prechemoradiotherapy (CRT) and post-CRT metabolic tumor volume (MTV) on positron emission tomography (PET) scanning with the pathologic response and survival in patients receiving preoperative CRT for esophageal cancer.The medical records of 37 patients with histologically confirmed Stage I-IVA esophageal cancer treated with CRT with or without surgical resection were reviewed. Of the 37 patients, 21 received preoperative CRT (57%) and 16 received definitive CRT (43%). All patients had a pre-CRT and 32 had a post-CRT PET scan. The MTV was measured on the pre-CRT PET and post-CRT PET scan, respectively, using a minimum standardized uptake value (SUV) threshold x, where x = 2, 2.5, 3, or the SUV maximum × 50%. The total glycolytic activity (TGA(x)) was defined as the mean SUV × MTV(x). The MTV ratio was defined as the pre-CRT PET MTV/post-CRT MTV. The SUV ratio was defined similarly. A single pathologist scored the pathologic response using a tumor regression grade (TRG) scale.The median follow-up was 1.5 years (range, 0.4-4.9). No significant correlation was found between any parameters on the pre-CRT PET scan and the TRG or overall survival (OS). Multiple post-CRT MTV values and post-TGA values correlated with the TRG and OS; however, the MTV(2.5(Post)) and TGA(2.5(Post)) had the greatest correlation. The MTV(2) ratio correlated with OS. The maximum SUV on either the pre-CRT and post-CRT PET scans or the maximum SUV ratio did not correlate with the TRG or OS. Patients treated preoperatively had survival similar compared with those treated definitively with a good PET response (p = 0.97) and significantly better than that of patients treated definitively with a poor PET response (p < 0.0001).The maximum SUV was not a predictive or prognostic parameter. The MTV(2.5) and TGA(2.5) were useful markers for predicting the response and survival on the post-CRT PET scan. The MTV(2) ratio also correlated with survival. Post-CRT PET can potentially guide therapy after CRT.

    View details for DOI 10.1016/j.ijrobp.2011.12.029

    View details for Web of Science ID 000308062700055

    View details for PubMedID 22381904

  • Positron Emission Tomography for Predicting Pathologic Response After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer Chennupati, S. K., Quon, A., Kamaya, A., Pai, R. K., La, T., Krakow, T. E., Graves, E., Koong, A. C., Chang, D. T. LIPPINCOTT WILLIAMS & WILKINS. 2012: 334-339

    Abstract

    To investigate whether before and after chemoradiotherapy (CRT) positron emission tomography (PET) predict for pathologic response after preoperative CRT in patients with locally advanced rectal adenocarcinoma.Thirty-five patients who underwent pre-CRT and post-CRT PET scans before surgery were included. All patients were staged with endoscopic ultrasound or high resolution CT. CRT was given with 50.4 Gy at 1.8 Gy per fraction and concurrent 5-fluorouracil-based chemotherapy. Surgery occurred at a median of 46 days (range, 27 to 112 d) after completing CRT. The maximum standardized uptake value (SUV(max)) and the metabolic tumor volume (MTV) using various minimum SUV thresholds (2, 2.5, 3) on the PET scans (MTV(2.0), MTV(2.5), MTV(3.0)) were determined. Post-CRT PET scans were done 3 to 5 weeks after completion of CRT. Pathologic response was assessed using the tumor regression grade (TRG) scale. Patients with complete or near-complete response (TRG=0 to 1) were considered pathologic responders. The pre-CRT and post-CRT PET scan SUV(max) and MTV values were correlated with TRG. The ?SUV(max) and ?MTV were correlated with TRG.No correlation was seen with SUV(max) (P=0.99), MTV(2.0) (P=0.73), MTV(2.5) (P=0.73), or MTV(3.0) (P=0.31) on the pre-CRT PET between pathologic responders versus nonresponders. No correlation was noted between SUV(max) (P=0.49), MTV(2.0) (P=0.73), MTV(2.5) (P=0.49), or MTV(3.0) (P=0.31) on the post-CRT PET scan and pathologic response. Finally, the ?SUV(max) (P=0.32), ?MTV(2.0) (P=0.99), ?MTV(2.5) (P=0.31), ?MTV(3.0) (P=0.31) did not correlate with pathologic response.Changes seen on PET have limited value in predicting for pathologic response of rectal cancer after preoperative neoadjuvant therapy.

    View details for DOI 10.1097/COC.0b013e3182118d12

    View details for Web of Science ID 000306599200006

    View details for PubMedID 21422989

  • Intensity-Modulated Radiotherapy for Pancreatic Adenocarcinoma Abelson, J. A., Murphy, J. D., Minn, A. Y., Chung, M., Fisher, G. A., Ford, J. M., Kunz, P., Norton, J. A., Visser, B. C., Poultsides, G. A., Koong, A. C., Chang, D. T. ELSEVIER SCIENCE INC. 2012: E595-E601

    Abstract

    To report the outcomes and toxicities in patients treated with intensity-modulated radiotherapy (IMRT) for pancreatic adenocarcinoma.Forty-seven patients with pancreatic adenocarcinoma were treated with IMRT between 2003 and 2008. Of these 47 patients, 29 were treated adjuvantly and 18 definitively. All received concurrent 5-fluorouracil chemotherapy. The treatment plans were optimized such that 95% of the planning target volume received the prescription dose. The median delivered dose for the adjuvant and definitive patients was 50.4 and 54.0 Gy, respectively.The median age at diagnosis was 63.9 years. For adjuvant patients, the 1- and 2-year overall survival rate was 79% and 40%, respectively. The 1- and 2-year recurrence-free survival rate was 58% and 17%, respectively. The local-regional control rate at 1 and 2 years was 92% and 80%, respectively. For definitive patients, the 1-year overall survival, recurrence-free survival, and local-regional control rate was 24%, 16%, and 64%, respectively. Four patients developed Grade 3 or greater acute toxicity (9%) and four developed Grade 3 late toxicity (9%).Survival for patients with pancreatic cancer remains poor. A small percentage of adjuvant patients have durable disease control, and with improved therapies, this proportion will increase. Systemic therapy offers the greatest opportunity. The present results have demonstrated that IMRT is well tolerated. Compared with those who received three-dimensional conformal radiotherapy in previously reported prospective clinical trials, patients with pancreatic adenocarcinoma treated with IMRT in our series had improved acute toxicity.

    View details for DOI 10.1016/j.ijrobp.2011.09.035

    View details for Web of Science ID 000300980300003

    View details for PubMedID 22197234

  • A DOSIMETRIC MODEL OF DUODENAL TOXICITY AFTER STEREOTACTIC BODY RADIOTHERAPY FOR PANCREATIC CANCER Murphy, J. D., Christman-Skieller, C., Kim, J., Dieterich, S., Chang, D. T., Koong, A. C. ELSEVIER SCIENCE INC. 2010: 1420-1426

    Abstract

    Dose escalation for pancreas cancer is limited by the tolerance of adjacent normal tissues, especially with stereotactic body radiotherapy (SBRT). The duodenum is generally considered to be the organ at greatest risk. This study reports on the dosimetric determinants of duodenal toxicity with single-fraction SBRT.Seventy-three patients with locally advanced unresectable pancreatic adenocarcinoma received 25 Gy in a single fraction. Dose-volume histogram (DVH) endpoints evaluated include V(5) (volume of duodenum that received 5 Gy), V(10), V(15), V(20), V(25), and D(max) (maximum dose to 1 cm(3)). Normal tissue complication probability (NTCP) was evaluated with a Lyman model. Univariate and multivariate analyses were conducted with Kaplan-Meier and Cox regression models.The median time to Grade 2-4 duodenal toxicity was 6.3 months (range, 1.6-11.8 months). The 6- and 12-month actuarial rates of toxicity were 11% and 29%, respectively. V(10)-V(25) and D(max) all correlated significantly with duodenal toxicity (p<0.05). In particular, V(15)?9.1 cm(3) and V(15)<9.1 cm(3) yielded duodenal toxicity rates of 52% and 11%, respectively (p=0.002); V(20)?3.3 cm(3) and V(20)<3.3 cm(3) gave toxicity rates of 52% and 11%, respectively (p=0.002); and D(max)?23 Gy and D(max)<23 Gy gave toxicity rates of 49% and 12%, respectively (p=0.004). Lyman NTCP model optimization generated the coefficients m=0.23, n=0.12, and TD(50)=24.6 Gy. Only the Lyman NTCP model remained significant in multivariate analysis (p=0.001).Multiple DVH endpoints and a Lyman NTCP model are strongly predictive of duodenal toxicity after SBRT for pancreatic cancer. These dose constraints will be valuable in future abdominal SBRT studies.

    View details for DOI 10.1016/j.ijrobp.2009.09.075

    View details for Web of Science ID 000284987800019

    View details for PubMedID 20399033

  • Expression of p16(INK4A) But Not Hypoxia Markers or Poly Adenosine Diphosphate-Ribose Polymerase Is Associated With Improved Survival in Patients With Pancreatic Adenocarcinoma Chang, D. T., Chapman, C. H., Norton, J. A., Visser, B., Fisher, G. A., Kunz, P., Ford, J. M., Koong, A. C., Pai, R. K. WILEY-BLACKWELL. 2010: 5179-5187

    Abstract

    Pancreatic cancer is associated with mutations in the tumor suppressor gene cyclin-dependent kinase inhibitor 2A (p16(INK4A) ), a regulator of the cell cycle and apoptosis. This study investigates whether immunohistochemical expression of p16(INK4A) as well as hypoxia markers and poly adenosine diphosphate-ribose polymerase (PARP) correlates with survival in patients with resected pancreatic adenocarcinoma.Seventy-three patients with pancreatic adenocarcinoma who underwent curative resection at Stanford University were included. From the surgical specimens, a tissue microarray was constructed using triplicate tissue cores from the primary tumor and used for immunohistochemical staining for the following markers: carbonic anhydrase IX, dihydrofolate reductase, p16(INK4A) , and PARP1/2. Staining was scored as either positive or negative and percentage positive staining. Staining score was correlated with overall survival (OS) and progression-free survival (PFS).Of the markers tested, only immunohistochemical expression of p16(INK4A) correlated with clinical outcome. On univariate analysis, p16(INK4A) expression in the tumor was associated with improved OS (P = .038) but not PFS (P = .28). The median survival for patients with positive versus negative p16(INK4A) staining was 28.8 months versus 18 months. On multivariate analysis, p16(INK4A) expression was associated with improved OS (P = .026) but not PFS (P = .25). Age (P = .0019) and number of nodes involved (P = .025) were also significant for OS. Adjuvant chemotherapy and margin status did not correlate with OS or PFS.Expression of p16(INK4A) is associated with improved OS in patients with resected pancreatic adenocarcinoma. Further investigation is needed for validation, given conflicting data in the published literature. .

    View details for DOI 10.1002/cncr.25481

    View details for Web of Science ID 000284047400009

    View details for PubMedID 20665497

  • Comparison of Intensity-Modulated Radiotherapy and 3-Dimensional Conformal Radiotherapy as Adjuvant Therapy for Gastric Cancer Minn, A. Y., Hsu, A., La, T., Kunz, P., Fisher, G. A., Ford, J. M., Norton, J. A., Visser, B., Goodman, K. A., Koong, A. C., Chang, D. T. JOHN WILEY & SONS INC. 2010: 3943-3952

    Abstract

    The current study was performed to compare the clinical outcomes and toxicity in patients treated with postoperative chemoradiotherapy for gastric cancer using intensity-modulated radiotherapy (IMRT) versus 3-dimensional conformal radiotherapy (3D CRT).Fifty-seven patients with gastric or gastroesophageal junction cancer were treated postoperatively: 26 with 3D CRT and 31 with IMRT. Concurrent chemotherapy was capecitabine (n=31), 5-fluorouracil (5-FU) (n=25), or none (n=1). The median radiation dose was 45 Gy. Dose volume histogram parameters for kidney and liver were compared between treatment groups.The 2-year overall survival rates for 3D CRT versus IMRT were 51% and 65%, respectively (P=.5). Four locoregional failures occurred each in the 3D CRT (15%) and the IMRT (13%) patients. Grade>or=2 acute gastrointestinal toxicity was found to be similar between the 3D CRT and IMRT patients (61.5% vs 61.2%, respectively) but more treatment breaks were needed (3 vs 0, respectively). The median serum creatinine from before radiotherapy to most recent creatinine was unchanged in the IMRT group (0.80 mg/dL) but increased in the 3D CRT group from 0.80 mg/dL to 1.0 mg/dL (P=.02). The median kidney mean dose was higher in the IMRT versus the 3D CRT group (13.9 Gy vs 11.1 Gy; P=.05). The median kidney V20 was lower for the IMRT versus the 3D CRT group (17.5% vs 22%; P=.17). The median liver mean dose for IMRT and 3D CRT was 13.6 Gy and 18.6 Gy, respectively (P=.19). The median liver V30 was 16.1% and 28%, respectively (P<.001).Adjuvant chemoradiotherapy was well tolerated. IMRT was found to provide sparing to the liver and possibly renal function.

    View details for DOI 10.1002/cncr.25246

    View details for Web of Science ID 000280677100025

    View details for PubMedID 20564136

  • ACTIVATORS OF PROTEIN-KINASE-C SELECTIVELY MEDIATE CELLULAR CYTOTOXICITY TO HYPOXIC CELLS AND NOT AEROBIC CELLS Koong, A. C., CHEN, E. Y., Kim, C. Y., Giaccia, A. J. PERGAMON-ELSEVIER SCIENCE LTD. 1994: 259-265

    Abstract

    By understanding the signal transduction pathways through which a cell responds to changes in environmental oxygen levels, we may be able to therapeutically exploit this response by manipulating these pathways.The human adenocarcinoma cell line A549 was exposed to varying durations of hypoxia alone and then plated for survival, or treated with PKC activating agents for 1 h before plating for survival. Western blots were used to determine the kinetics of PKC epsilon and phospholipase C induction.The level of hypoxic killing was directly related to the time of exposure and inversely related to the level of oxygen in the environment. Exposure of the cells to protein kinase C (PKC) activators for 1 h after chronic hypoxic exposure increased cell killing by at least an additional three logs beyond that found for hypoxia alone. Treatment of cells with an inactive phorbol ester 4 alpha-phorbol-12,13-didecanoate (PDA) resulted in no increase in hypoxic cell killing, even at the highest concentrations of PDA which produced no detectable toxicity under normal aerobic conditions. Using inhibitors of phospholipases A2 and C, we were able to completely inhibit the additional hypoxic cell killing induced by TPA, but not the uninduced hypoxic cell killing.These studies suggest that accumulation of phospholipid breakdown products may be responsible for TPA induced cell killing, and that hypoxic cells differ from aerobic cells in their ability to tolerate these products.

    View details for Web of Science ID A1994NN51200007

    View details for PubMedID 8195017

  • THE REGULATION OF GRP78 AND MESSENGER-RNA LEVELS BY HYPOXIA IS MODULATED BY PROTEIN-KINASE-C ACTIVATORS AND INHIBITORS Koong, A. C., AUGER, E. A., CHEN, E. Y., Giaccia, A. J. RADIATION RESEARCH SOC. 1994: S60-S63

    Abstract

    In this study, we have shown that steady-state levels of glucose-regulated 78 kDa (GRP78) protein and messenger RNA increase during a 5-h exposure to 0.02% oxygen. This increase in GRP78 protein and mRNA induced by hypoxia can be abolished by a 1-h pretreatment of cells before hypoxia with the protein kinase C (PKC) inhibitors staurosporine and H7 at concentrations at which the drugs themselves do not cause cytotoxicity. Although all studies using protein kinase inhibitors must be interpreted with caution, staurosporine and H7 have been shown to be potent inhibitors of PKC activity, suggesting a role for PKC in mediating the transcriptional regulation of GRP78 by hypoxia. Further support for PKC in regulating GRP78 gene expression by hypoxia stems from gel-mobility shift studies in mixtures of nuclear extracts from aerobic or hypoxic cells with a 36 bp region of the GRP78 promoter (-170 to -135). Binding of this factor could be inhibited by pretreating cells with the PKC inhibitor staurosporine before hypoxia or activated by treating cells with the PKC-activating phorbol ester TPA. These data suggest that activation of this hypoxia-responsive factor is sensitive to oxygen levels and seems to be mediated through a PKC signal transduction pathway.

    View details for Web of Science ID A1994NF37900016

    View details for PubMedID 8146329

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