Clinicopathological Features of Hereditary Breast Cancer.

The possible role of germline mutations of BRCA1 and BRCA2 as causative agents of familial breast cancer was assessed. Their possible involvement in the carcinogenesis of hereditary breast cancer was investigated using 63 clinically suspect families. Twenty-one lineages (33.3%) had mutations in one of the two BRCA genes. This relatively low incidence suggested that germline mutations in unknown genes are involved in the carcinogenesis of hereditary breast cancer in the Japanese population. However, the clinicopathological features characteristic of hereditary breast cancer, such as early disease onset, a high incidence of bilateral breast cancer, and a high incidence of multiple primary carcinomas in other organs were confirmed in the present study.