The birth of the subspecialty of medical oncology and examples of its early scientific foundations.

"Passion is not accepting defeat."--Emil Frei III. In the early 1950s, an experimental and clinical program characterized by unique cross-fertilization was developed. The clinical importance of experimental animal models in drug screening and in establishing key chemotherapy concepts and the role of the pioneers of medical oncology in the design of the various phases of drug trials, using childhood acute leukemia and breast cancer as models, are discussed. Over a short time and with only a few drugs, principles of chemotherapy were laid out, which led to cures in such diseases as childhood acute leukemia and Hodgkin's disease and to improved disease-free survival in breast cancer. It is these and other achievements that paved the way to medical oncology. At the instigation of the American Society of Clinical Oncology (ASCO), the American Board of Internal Medicine made inquiries about a subspecialty in oncology. ASCO and B. J. Kennedy, MD, played key roles in the events leading to the official recognition of medical oncology as a new subspecialty of internal medicine in 1972.