BRCA1/2 Mutation Frequency is HIGH in Japanese Triple-Negative Breast Cancer Patients

抄録

Germline mutations of BRCA1/2 genes cause hereditary breast and/or ovarian cancer. However, whether guidelines like those of the National Comprehensive Cancer Network (NCCN) can suitably predict the likelihood of BRCA1/2 mutations in the Japanese population is unclear. Methods BRCA1/2 gene mutation frequencies were investigated in relation to parameters such as age, family history (FH), and breast cancer subtype using data collected from 922 Japanese breast cancer patients who underwent surgery between September 2010 and June 2013. BRCA1/2 mutations were present in 15 of 57 (26.3%) tested patients. The frequency of the mutations was not significantly related to age. Among the 180 patients who reported an FH of breast cancer, 11 of the 37 who were tested (29.7%) were positive for BRCA1/2 mutations. Of those with an FH of ovarian cancer (n = 34), seven of 12 patients tested (58.3%) were carriers of BRCA1/2 (P = 0.013). Six of these seven carriers were triple-negative breast cancer (TNBC) patients. In all, there were 97 TNBC patients, and the presence of the BRCA1/2 mutation in this subgroup was significantly greater than in non-TNBC patients, with 12 of 17 TNBC patients (70.5%) testing positive (P = 0.03). There were 59 TNBC patients < 60 years of age, and of the 16 (27.1%) who underwent BRCA1/2 genetic testing, 11 (68.8%) were found to have mutations in BRCA1/2. Among the TNBC patients, 29 also reported an FH of breast or ovarian cancer; of these, nine of the 13 tested (69.2%) were positive for a BRCA1/2 mutation. The data demonstrate that BRCA1/2 mutations are observed more frequently in TNBC patients, especially those < 60 years of age or in combination with an FH of breast and/or ovarian cancer, suggesting that some of the NCCN guidelines can adequately predict BRCA1/2 carriers in the Japanese population.