A large number of studies have shown that the occurrence, development and inheritance of breast cancer are closely related to BRCA1/2 gene mutations. Women with mutations in the BRCA1 and BRCA2 genes have a significantly increased lifetime risk of breast cancer and ovarian cancer.

Breast cancer caused by BRCA1/2 gene mutation exhibits the tendency of familial inheritance. If one party of both parents carries gene mutation, the mutation is likely to transmit to the offspring at a probability of 50%.

In view of the hazard caused by BRCA1/2 gene mutation, the National Comprehensive Cancer Network (NCCN) and the Breast Cancer Professional Committee of the Chinese Anti-Cancer Association have formulated targeted clinical practice guidelines, which include the BRCA1/2 gene detection standards, and emphasize the necessity of genetic screening for breast cancer.

The entire coding regions of the two genes, BRCA1 and BRCA2, totally about 16,000 sites.