The Division of Pediatric Hematology/Oncology of Babies Hospital (the pediatric section of Columbia University College of Physicians and Surgeons) will continue its participation in the Children's Cancer Study Group. The purpose of these studies is to devise optimal management for childhood cancer, and to evaluate the biology of childhood tumors. The group at Babies (together with its major affiliate, the Division of Pediatric Hematology/Oncology at New York University) will enter in studies designed in cooperation with other members of the Children's Cancer Study Group all patients with childhood cancer; it will provide for all patient management standardized to group requirements, including all required laboratory investigations and biological sampling; it will keep accurate records and transmit them promptly to the Group Headquarters for evaluation. In addition to patient entry, investigators from the group at Babies will participate in protocol design and strategy of experimental approach, providing the input of their expertise and specific resources. The Division of Pediatric Hematology/Oncology will foster the development of research in the area of childhood cancer, with an eye to providing research input that could be expanded to group-wide experimentation. Areas under current investigation by individual members include: a) use of monoclonal antibodies to melanoma for cross-reactivity with neuroblastoma; b) immunological characterization of leukemia and lymphoma cells; c) use of chelating and SH- group agents to decrease toxicity of chemotherapy; d) identification of biochemical markers of malignancy; e) role of idiotypic immunoglobulins in transplantation; f) psychological late effects of treatment in childhood leukemia; g) advances in the management of osteosarcoma; h) use and complications of central access line in childhood cancer.