Tumor Variation in Families With Breast Cancer

This study documents types of malignant neoplasms found in members of 34 families who were selected for investigation because of their having two or more members affected with breast cancer. The data indicate that the members of some families with familial breast cancer have a relatively high predisposition for cancer of the colon, while the members of other families with familial breast cancer show relatively high predispositions, respectively, for gastric, ovarian, and endometrial carcinoma, and some for a complex of brain tumors, sarcoma, and leukemia. The observations are consistent with concepts of multiple causes involving the interactions of different genetic and environmental factors that structure different patterns of tumor association and predisposition.