Six families prone to ovarian cancer.

Six families are presented with multiple cases of ovarian cancer, mainly serous cystadenocarcinoma. Three families had concomitant aggregation of breast cancer, suggesting genetic determinants common to both tumors. The exceptional cancer risk in these families prompted prophylactic oophorectomy in 14 asymptomatic women from four families. Review of the original microscopic sections from 8 women revealed that 3, representing two families, had abnormalities of ovarian surface epithelium and mesothelial tissue, which may be of etiologic significance and portend neoplastic changes. To enable early detection and prevention of ovarian cancer, new diagnostic techniques and etiologic studies should be applied whenever possible to high-risk families.