Breast cancer is a malignant tumor with a genetic predisposition. For women with a family history of breast cancer, their risk of developing breast cancer is two to three times higher than that of the general population. Women who carry breast cancer susceptibility genes have a lifetime risk of breast cancer of 60% to 70%, which is why the famous American actress Angelina Jolie underwent a preventive bilateral mastectomy to minimize the risk of breast cancer. So, how do you know if you have a family history of breast cancer and if you have the possibility of hereditary breast cancer? Simply put, a family history of breast cancer is defined as having a first-degree, second-degree or third-degree relative who has breast cancer, including male relatives with breast cancer. A family history of breast cancer does not necessarily mean that the cancer is hereditary. Breast cancer is only hereditary if it is clearly carried by a breast cancer susceptibility gene, which can be determined by genetic testing. There are two genes that have been identified as directly related to the risk of breast cancer: BRCA1 and BRCA2, which can be tested by scraping oral mucosa cells and blood tests. Does a family history of breast cancer require breast cancer genetic testing? Because of the high cost of breast cancer genetic testing (around $6,000) and the fact that it is not covered by medical insurance, the test is currently recommended only for people with a high genetic risk of breast cancer. Breast cancer genetic high risk group refers to: (1) BRCA1 and BRCA2 gene carriers among blood relatives; (2) Breast cancer patients with age of onset less than 50 years old among close relatives; (3) Breast cancer and ovarian cancer among close relatives at the same time or successively; (4) Male breast cancer patients in the family. What is the treatment for breast cancer susceptibility gene? Prophylactic bilateral mastectomy and post-operative breast reconstruction are usually recommended in the United States. However, in China, aggressive treatment is not recommended because a positive test result only increases the lifetime risk of breast cancer, not necessarily the eventual development of breast cancer, and mastectomy is invasive and risky, and reconstructive surgery after mastectomy faces high costs and related postoperative complications. Therefore, for those who have a positive test result, it is recommended to have a mammogram early, usually once a year starting from the age of 20 or above, and to have surgery in time when cancer signs are detected, which will not affect the overall survival.