Clinicopathological Characteristics of Breast Cancers in Japanese Women Who Carry Germ line Mutation of BRCA1 or BRCA2

Abstract

Among 113 Japanese breast cancer families, we have identified 15（13 ％）and 21（19 ％）deleterious germline mutations in BRCA1 and BRCA2 genes, respectively. Among patients with BRCA1 or BRCA2 mutation carrier, breast cancers occurred in significantly younger women with higher frequency of bilateral breast cancers as compared with non-carriers. The estimated cumulative lifetime risk of breast cancer for women who carry BRCA1 or BRCA2 mutations was nearly 80%. In BRCA1 breast cancers, a higher rate of histological grade III and a higher frequency of estrogen-receptor negativity were characterized as compared to sporadic cancers. On the contrary, there was no significant difference in cancers between BRCA2 mutation carriers and non-carriers. These clinicopathological factors found in Japanese BRCA1 or BRCA2 mutation carriers seem to be similar with those of Caucasian mutation carriers.