The Washington University Medical Center in St. Louis is one of the 39 full member institutions, 48 affiliate, 12 consortia and 9 CCOP institutions of the Pediatric Oncology Group who has pooled their patient resources and scientific expertise to study the natural history of childhood cancer, develop and compare effective therapeutic regimens and investigate the toxicity and effectiveness of new anticancer agents in the treatment of children with cancer. Additionally tumor specimens and occasionally normal tissue and blood samples are collected to determine more about the basic cancer biology and pathology of the disease. Group studies are ongoing in epidemiology, cancer control, pharmacology and pharmacokinetics. The investigators at the Washington University Medical Center include pediatric oncologists, radiologists, radiation oncologists, cytogenetists, neurologists, surgeons, and pathologists. All children with malignant disease are placed on cooperative group protocols if they are eligible and if informed consent is obtained. Data accessioned at the time the patient is placed on study protocol, during the study, and when off therapy is submitted to the Group Statistical Office for data analysis, interpretation and eventual publication. The investigators at Washington University Medical Center serve in multiple administrative and research capacities for the Group. The diagnostic studies, pathological findings, surgical procedure and therapeutic plan for all new patients and patients who relapse are discussed at the weekly Tumor Board Conference. The Principal Investigator has a phase I contract and works with 16 other POG institutions to establish the maximum tolerated dose of a new agent along with the pharmacology and, if indicated, the biologic response of the agent.