We are requesting continuation funds for a research training program in the Pediatric Oncology Program at the Fred Hutchinson Cancer Research Center and the Department of Pediatrics, University of Washington. The purpose of the proposed program is to train promising physicians to become independent investigative pediatric oncologists. In the first year of the program, which is funded by sources other than this grant, trainees receive intensive exposure to clinical care and clinical research. Their second and third years, the trainees commit themselves commit themselves to a major research effort. Research projects in the areas of hematopoietic cell transplant research, leukemia/lymphoma immunology and immunotherapy, transplantation biology, normal and malignant hematopoiesis, human immunogenetics, neurooncology, cancer survivorship and molecular biology, as well as other programs, are available. The aim of the projects will be to contribute new and useful information relevant to pediatric oncology and to develop the research capabilities of the trainees to allow them to establish themselves as independent investigators. Physicians who have completed three years of training as residents in pediatrics will be eligible. Those most qualified and motivated to enter into investigative endeavors will be selected. In the past, many of the applicants have had previous laboratory experience. Of the twenty-one trainees supported by this NRSA who have completed their training during the past ten years, nineteen have remained in academic pediatric oncology. We are requesting funding for two postdoctoral fellowships per year in a two-year program (a total of four positions). This program involves the laboratory and clinical research facilities of the Fred Hutchinson Cancer Research Center and the University of Washington; the clinical facilities of the Division of Hematology- Oncology at the Seattle Children's Hospital, the primary clinical pediatric service of the University of Washington; and the clinical facilities of the pediatric oncology service of te Fred Hutchinson Cancer Research Center.