There are three main purposes of genetic testing for breast cancer, which are risk prediction, guidance of treatment, and evaluation of heredity. 1. Risk estimation: through genetic testing, the risk index of breast cancer can be derived, which can provide the basis for whether chemotherapy is needed for postoperative breast cancer patients. 2. Guiding treatment: Finding the variation of tumor gene-related information of breast cancer, providing specific targeting plan for doctors’ treatment, formulating personalized treatment plan, and giving targeted drug treatment according to the presence or absence of a certain gene, which is more effective. 3. Evaluation of heredity: According to the genetic information of breast cancer patients, effective interventions can be provided to their immediate family members to reduce the risk of cancer. It is recommended that breast cancer patients seek medical advice in time and decide whether to undergo genetic testing after consulting their doctors.