- Pediatric Hematology-Oncology
Clinical Assistant Professor, Pediatrics - Hematology & Oncology
Solid Tumors, Bone Sarcomas, Global Oncology, Health Disparities
Spitzoid melanoma is a specific morphologic variant of melanoma that most commonly affects children and adolescents, and ranges on the spectrum of malignancy from low grade to overtly malignant. These tumors are generally driven by fusions of ALK, RET, NTRK1/3, MET, ROS1 and BRAF1,2. However, in approximately 50% of cases no genetic driver has been established2. Clinical whole-genome and transcriptome sequencing (RNA-Seq) of a spitzoid tumor from an adolescent revealed a novel gene fusion of MAP3K8, encoding a serine-threonine kinase that activates MEK3,4. The patient, who had exhausted all other therapeutic options, was treated with a MEK inhibitor and underwent a transient clinical response. We subsequently analyzed spitzoid tumors from 49patients by RNA-Seq and found in-frame fusions or C-terminal truncations of MAP3K8 in 33% of cases. The fusion transcripts and truncated genes all contained MAP3K8 exons 1-8 but lacked the autoinhibitory final exon. Data mining of RNA-Seq from the Cancer Genome Atlas (TCGA) uncovered analogous MAP3K8 rearrangements in 1.5% of adult melanomas. Thus, MAP3K8 rearrangements-uncovered by comprehensive clinical sequencing of a single case-are the most common genetic event in spitzoid melanoma, are present in adult melanomas and could be amenable to MEK inhibition.
View details for PubMedID 30833747
Tumor response assessments on positron emission tomography (PET)/magnetic resonance imaging (MRI) scans require correct quantification of radiotracer uptake in tumors and normal organs. Historically, MRI scans have been enhanced with gadolinium (Gd)-based contrast agents, which are now controversial due to brain deposition. Recently, ferumoxytol nanoparticles have been identified as an alternative to Gd-based contrast agents because they provide strong tissue enhancement on MR images but are not deposited in the brain. However, it is not known if the strong T1- and T2-contrast obtained with iron oxide nanoparticles such as ferumoxytol could affect MR-based attenuation correction of PET data. The purpose of our study was to investigate if ferumoxytol administration prior to a 2-deoxy-2-[18F]fluoro-D-glucose [18F]FDG PET/MR scan would change standardized uptake values (SUV) of normal organs.Thirty pediatric patients (6-18 years) with malignant tumors underwent [18F]FDG-PET/MR scans (dose 3 MBq/kg). Fifteen patients received an intravenous ferumoxytol injection (5 mg Fe/kg) prior to the [18F]FDG-PET/MR scans (group 1). Fifteen additional age- and sex-matched patients received unenhanced [18F]FDG-PET/MR scans (group 2). For attenuation correction of PET data, we used a Dixon-based gradient echo sequence (TR 4.2 ms, TE 1.1, 2.3 ms, FA 5), which accounted for soft tissue, lung, fat, and background air. We used a mixed linear effects model to compare the tissue MRI enhancement, quantified as the signal-to-noise ratio (SNR), as well as tissue radiotracer signal, quantified as SUVmean and SUVmax, between group 1 and group 2. Alpha was assumed at 0.05.The MRI enhancement of the blood and solid extra-cerebral organs, quantified as SNR, was significantly higher on ferumoxytol-enhanced MRI scans compared to unenhanced scans (p < 0.001). However, SUVmean and SUVmax values, corrected based on the patients' body weight or body surface area, were not significantly different between the two groups (p > 0.05).Ferumoxytol administration prior to a [18F]FDG PET/MR scan did not change standardized uptake values (SUV) of solid extra-cerebral organs. This is important, because it allows injection of ferumoxytol contrast prior to a PET/MRI procedure and, thereby, significantly accelerates image acquisition times.
View details for DOI 10.1007/s11307-019-01409-3
View details for PubMedID 31325083
Most children with cancer live in resource-limited countries where malnutrition is often prevalent. We identified the relationship between malnutrition and treatment-related morbidity (TRM), abandonment of therapy, and survival of children with cancer in Nicaragua to better inform targeted nutritional interventions.We conducted a retrospective review of patients aged 6 months to 18 years with newly diagnosed acute lymphoblastic leukemia, acute myeloid leukemia (AML), Wilms tumor, Hodgkin lymphoma, or Burkitt lymphoma (BL) who were treated between January 1, 2004, and December 31, 2007 at Children's Hospital Manuel de Jesus Rivera in Managua, Nicaragua. Statistical analysis examined the relations among nutritional status and cancer type, risk category, TRM, and event-free survival (EFS).Sixty-seven percent of patients (189/282) were malnourished at diagnosis. Malnutrition was highest among patients with Wilms tumor (85.7%), BL (75%), and AML (74.3%). A total of 92.2% of patients (225/244) experienced morbidity during the first 90 days. Malnutrition was associated with severe infection (P = 0.033). Severely malnourished patients had ≥grade 3 TRM on more days (P = 0.023) and were more likely to experience severe TRM on >50% of days (P = 0.032; OR, 3.27 [95% CI, 1.05-10.16]). Malnourished patients had inferior median EFS (2.25 vs. 5.58 years; P = 0.049), and abandoned therapy more frequently (P = 0.015).In Nicaragua, pediatric oncology patients with malnutrition at diagnosis experienced increased TRM, abandoned therapy more frequently, and had inferior EFS. Standardized nutritional evaluation of patients with newly diagnosed cancer and targeted provision of nutritional support are essential to decrease TRM and improve outcomes.
View details for DOI 10.1002/pbc.26590
View details for PubMedID 28449403