2008 Volume 8 Issue 2 Pages 40-43
Mutation analysis of BRCA1 and BRCA2 was conducted in 113 Japanese familial breast cancer （FBC） patients. Fifteen deleterious mutations （13.3%） were identified in BRCA1 and 21 deleterious mutations（18.6%） were identified in BRCA2. These findings demonstrate that the cumulative frequency of BRCA1 and BRCA2 mutations in Japanese breast cancer families（31.9%）is within the range observed in Caucasian breast cancer families. The mean age at the time of diagnosis of BRCA1-associated FBCs and that of BRCA2-associated FBCs（44 years for both）were significantly younger than that of the control group（54 years）and the incidence of bilateral tumors was significantly higher in the BRCA1-associated FBCs （32%）and BRCA2-associated FBCs（29%）than in the control group（6%）. BRCA1-associated FBCs showed a significant increase in histologic grade 3 tumors（p ＜ 0.01） and estrogen receptor negative tumors（p ＜ 0.01）. However, such characteristics were not observed in the BRCA2-associated FBCs. BRCA1-associated FBCs, but not BRCA2-associated FBCs, seem to have biologically aggressive phenotypes.