The CORE Program is designed to encompass the cancer research activities of The Wistar Institute. The key objectives of the program concern: 1) modulation of the phenotypic expression of cellular antigens in normal and malignant cells; 2) components of the immune response and their interaction in the host-tumor response; 3) structure changes in cell surface membranes in normal and transformed cells; 4) virus-cell interaction in neoplastic transformation - determination of some regulatory events involved in this interaction; 5) the role of chemical carcinogens in oncogenesis; 6) regulatory elements associated with cell growth and the phenotypic expression of specific cell functions; 7) application of quantitative cytochemistry and cell cycle analysis to tumor biology; and 8) genetic analysis of regulatory aspects of oncogenesis. In pursuit of these objectives, a wide variety of biochemical, biophysical and biological methods will be employed. BIBLIOGRAPHIC REFERENCES: Croce, C.M., D.Aden and H. Koprowski. Somatic cell hybrids between mouse peritoneal macrophages and SV40 transformed human cells. III. Tumorigenicity of diploid hybrid cells. Science, 120:1200-1202, 1975. Croce, C.M., D. Aden and H. Koprowski. Somatic cell hybrids between mouse peritoneal macrophages and SV40 transformed human cells. II. Presence of the human chromosome 7 carrying the SV40 genome in the cells of tumors induced by the hybrid cells. Proc. Nat. Acad. Sci., U.S.A. 72: 1397-1400, 1975.