The breast cancer susceptibility gene BRCA1/2 is a gene directly associated with hereditary breast cancer. Normal BRCA1/2 is involved in DNA damage repair of genetic material, maintaining cellular homeostasis and normal growth, thereby inhibiting malignant tumorigenesis. If a deleterious mutation occurs in the BRCA1/2 gene, it predisposes to the development of cancer, and deleterious mutations are often passed on to the next generation. People with mutations in this gene are significantly more likely to develop breast and ovarian cancer and some other types of cancer, and are familially aggregated, have a younger age of onset, and are more likely to involve both breasts. Hereditary breast cancer genetic testing criteria: 1. Carriers of BRCA1/BRCA2 gene mutation in blood relatives. Breast cancer patients who meet one or more of the following conditions: ① Age at disease onset less than or equal to 45 years old; ② Age at disease onset less than or equal to 50 years old and have a consanguineous relative who is also a breast cancer patient with age at disease onset less than or equal to 50 years old and/or a patient with ovarian epithelial cancer/fallopian tube cancer/primary peritoneal cancer of any age; ③ Having two primary breast cancers with age at first disease onset less than or equal to 50 years old; ④ Having two primary breast cancers with age at disease onset less than or equal to 50 years old (4) 2 or more blood relatives with breast cancer and/or ovarian epithelial cancer, fallopian tube cancer, or primary peritoneal cancer at the same time, regardless of the age of onset; (5) male blood relatives with breast cancer; (6) combined history of ovarian epithelial cancer, fallopian tube cancer, or primary peritoneal cancer. 3.Patients with ovarian epithelial cancer, fallopian tube cancer and primary peritoneal cancer. 4.Male breast cancer patients. 5.People with the following family history in general: ①Any of the above conditions among the first or second degree relatives with blood relationship; ②Two or more breast cancer patients (at least one with age of onset less than or equal to 50 years) and/or ovarian epithelial cancer/fallopian tube cancer/primary peritoneal cancer patients among the third degree relatives with blood relationship.