Breast cancer: genetics

The observation that some families have an excess of breast cancers, not readily accounted for by chance, is not new. Breast cancer families have been recognized since Ancient Roman times1. One of the earliest and most striking published reports was by a French physician, Paul Broca, who in 1866 reported a four-generation family where breast cancer had affected ten out of twenty-four women2. It is only in the last 10 years, however, that significant advances have led to a better understanding of familial clustering of this disease.