Clues to cancer risk: biologic markers.

Two large kindreds manifesting the "cancer family syndrome" have been studied. Genetic and biologic studies reveal markers which have important implications for cancer detection, control and prevention. Valuable markers may be found in the major histocompatibility system, HL-A. The presence of carcinoembryonic antigen and SV-40 viral transformation of skin fibroblasts are other possibly important markers. Relationships of the ABO blood groups to cancer are under intensive study, as is the hepatitis-associated antigen.