Cancer is the leading cause of death from disease in American children past age 1 year. The objectives of this center are (1) to determine etiology and mechanisms of childhood cancer and ultimately methods of prevention, (2) to devise and evaluate new methods of treating childhood cancer, and (3) to promptly bring the benefits of new information concerning childhood cancer to children with the disease. The methods are: 1. Basic biological research to determine the chemical nature of growth and differentiation and its control and to establish the mechanisms of oncogenesis using DNA and RNA virus-cell systems. 2. Basic and applied clinical investigation to determine the nature and etiology of childhood neoplasms and how they can be destroyed or controlled by chemical and physical means. 3. Health care demonstration of new methods of childhood cancer control involving not only this hospital but medical centers in other cities and physicians in practice throughout the region. 4. Dissemination of information and methods concerning childhood cancer research through (a) research and clinical training programs for medical, nursing and graduate students and for physicians, scientists and nurses and (b) presentations and publications.