To investigate the mutation status of BRCA1/2 exon region and its relationship with clinicopathological characteristics in hereditary breast cancer patients.

This was a retrospective study. According to the inclusion and exclusion criteria, 100 patients diagnosed with hereditary breast cancer in the Department of Breast Surgery, Shanxi Provincial People’s Hospital from February 2004 to February 2006 were enrolled in this study. The mutation status of BRCA1/2 gene was detected by next-generation sequencing. The related clinicopathological data were collected, including age, histological grade, lymph node status, ER, PR and HER-2 expression. The mutation type was compared between BRCA1 and BRCA2 using Fisher’s exact probability test.The relationship of BRCA1/2 mutation with clinicopathological characteristics was analyzed by χ² test.

Six patients carried BRCA1 mutation and 11 patients carried BRCA2 mutation in 100 patient with hereditary breast cancer. In 6 patients with BRCA1 mutation, there were 4 with frameshift mutation and 2 with nonsense mutation. In 11 patients with BRCA2 mutation, there were 4 with frameshift mutation and 7 with nonsense mutation. There was no statistically significant difference between two groups (P=0.335). In the patients with breast cancer of histological grade 1 and 2, the patients with BRCA1 mutation, BRCA2 mutation and no BRCA1/2 mutation accounted for 4.4% (4/91), 8.8% (8/91) and 86.8% (79/91), respectively. In the patients with breast cancer of histological grade 3, the patients with BRCA1 mutation, BRCA2 mutation and no BRCA1/2 mutation accounted for 2/9, 3/9 and 4/9, respectively. There was statistically significant difference between two groups (χ²=9.398, P=0.007). In HER-2 negative patients, the proportion of patients with BRCA1 mutation, BRCA2 mutation and no BRCA1/2 mutation was 10.7% (6/56), 16.1% (9/56) and 73.2% (41/56), respectively. In HER-2 positive patients, the proportion of patients with BRCA1 mutation, BRCA2 mutation and no BRCA1/2 mutation was 0 (0/44), 4.5% (2/44) and 95.5% (42/44), respectively. There was statistically significant difference between two groups (χ²=9.072, P=0.007).

There are some differences in the distribution of BRCA1/2 mutation in hereditary breast cancer patients with different histological grades and HER-2 expression. This study increases the clinical genetic data of hereditary breast cancer and provides a theoretical reference for the individualized precision treatment.