Carcinoma of the breast in three siblings

Reported are three siblings, a sister and 2 brothers, who had breast cancer. The paternal grandmother of the proband was known to have had breast cancer. It is our belief that this report supports further the genetic etiology of certain breast cancers. The study examines the literature with regard to genetically transmitted female breast cancer and also implies a genetic etiology of male breast cancer. Of special interest is the fact that the female sibling had bilateral breast cancer during her premenopausal years and that one of the two brothers also developed his lesion at an early age, 41 years.