Abstract
This study comprises five cancer prone families with one or more occurrences of melanoma in context with a variety of other histologic types of cancer, including an excess of multiple primary malignant tumors. The genetic mode of transmission of cancer in each family was consistent with a dominant factor which has seemingly predisposed these patients to a general cancer diathesis. The tumor spectrum included melanoma and cancers of the breast, gastrointestinal tract, lung and lymphoproliferative system. Recently, S 1 an S 2 antigens were noted to occur with melanoma and the same variety of tumors which have occurred in these five families.