Clinical Focus

  • Pediatric Hematology-Oncology

Academic Appointments

Professional Education

  • Fellowship:Lucile Packard Children's Hospital (2011) CA
  • Residency:Children's Hospital Oakland (1997) CA
  • Medical Education:UCSF School of Medicine (1994) CA
  • Board Certification: Pediatric Hematology-Oncology, American Board of Pediatrics (2004)


2015-16 Courses


All Publications

  • A Pediatric Case of T-Cell Prolymphocytic Leukemia PEDIATRIC BLOOD & CANCER Mitton, B., Coutre, S., Willert, J., Schlis, K., Porteus, M., Kharbanda, S., Agarwal-Hashmi, R. 2015; 62 (6): 1061-1062


    T-cell Prolymphocytic Leukemia (T-PLL) is a rare entity, and to date has never been reported in children. Here, we describe the first pediatric case of T-PLL in a 16-year old male and review his clinical course through treatment. He underwent therapy with alemtuzumab and pentostatin, which was successful in inducing initial remission. He then underwent an allogeneic matched sibling stem cell transplant following a myeloablative conditioning regimen and remains disease-free 1.5 years after diagnosis. Pediatr Blood Cancer 2014 Wiley Periodicals, Inc.

    View details for DOI 10.1002/pbc.25336

    View details for Web of Science ID 000353231500025

  • Population pharmacokinetics of bevacizumab in children with osteosarcoma: implications for dosing. Clinical cancer research Turner, D. C., Navid, F., Daw, N. C., Mao, S., Wu, J., Santana, V. M., Neel, M., Rao, B., Willert, J. R., Loeb, D. M., Harstead, K. E., Throm, S. L., Freeman, B. B., Stewart, C. F. 2014; 20 (10): 2783-2792


    To describe sources of interindividual variability in bevacizumab disposition in pediatric patients and explore associations among bevacizumab pharmacokinetics and clinical wound healing outcomes.Before tumor resection, three doses of bevacizumab (15 mg/kg) were administered to patients (median age, 12.2 years) enrolled in a multi-institutional osteosarcoma trial. Serial sampling for bevacizumab pharmacokinetics was obtained from 27 patients. A population pharmacokinetic model was fit to the data, and patient demographics and clinical chemistry values were systematically tested as predictive covariates on model parameters. Associations between bevacizumab exposure and wound healing status were evaluated by logistic regression.Bevacizumab concentration-time data were adequately described by a two-compartment model. Pharmacokinetic parameter estimates were similar to those previously reported in adults, with a long median (range) terminal half-life of 12.2 days (8.6 to 32.4 days) and a volume of distribution indicating confinement primarily to the vascular space, 49.1 mL/kg (27.1 to 68.3 mL/kg). Body composition was a key determinant of bevacizumab exposure, as body mass index percentile was significantly (P < 0.05) correlated to body-weight normalized clearance and volume of distribution. Furthermore, bevacizumab exposure before primary tumor resection was associated with increased risk of major wound healing complications after surgery (P < 0.05).A population pharmacokinetic model for bevacizumab was developed, which demonstrated that variability in bevacizumab exposure using weight-based dosing is related to body composition. Bevacizumab dosage scaling using ideal body weight would provide an improved dosing approach in children by minimizing pharmacokinetic variability and reducing likelihood of major wound healing complications. Clin Cancer Res; 20(10); 2783-92. 2014 AACR.

    View details for DOI 10.1158/1078-0432.CCR-13-2364

    View details for PubMedID 24637635

  • A transcriptional response to Wnt protein in human embryonic carcinoma cells. BMC developmental biology Willert, J., Epping, M., Pollack, J. R., Brown, P. O., Nusse, R. 2002; 2: 8-?


    Wnt signaling is implicated in many developmental decisions, including stem cell control, as well as in cancer. There are relatively few target genes known of the Wnt pathway.We have identified target genes of Wnt signaling using microarray technology and human embryonic carcinoma cells stimulated with active Wnt protein. The ~50 genes upregulated early after Wnt addition include the previously known Wnt targets Cyclin D1, MYC, ID2 and betaTRCP. The newly identified targets, which include MSX1, MSX2, Nucleophosmin, Follistatin, TLE/Groucho, Ubc4/5E2, CBP/P300, Frizzled and REST/NRSF, have important implications for understanding the roles of Wnts in development and cancer. The protein synthesis inhibitor cycloheximide blocks induction by Wnt, consistent with a requirement for newly synthesized beta-catenin protein prior to target gene activation. The promoters of nearly all the target genes we identified have putative TCF binding sites, and we show that the TCF binding site is required for induction of Follistatin. Several of the target genes have a cooperative response to a combination of Wnt and BMP.Wnt signaling activates genes that promote stem cell fate and inhibit cellular differentiation and regulates a remarkable number of genes involved in its own signaling system.

    View details for PubMedID 12095419

  • Metastatic appendiceal carcinoid tumor in a child MEDICAL AND PEDIATRIC ONCOLOGY Volpe, A., Willert, J., Ihnken, K., Treynor, E., Moss, R. L. 2000; 34 (3): 218-220

    View details for Web of Science ID 000085646200012

    View details for PubMedID 10696132

  • Congenital mesoblastic nephroma: A rare cause of perinatal anemia JOURNAL OF PEDIATRICS Willert, J. R., Feusner, J., Beckwith, J. B. 1999; 134 (2): 248-248

    View details for Web of Science ID 000078583700030

    View details for PubMedID 9931540

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