Breast cancer is hereditary and the following groups are at high risk of hereditary breast cancer: (1) A consanguineous relative who is a carrier of the BRCA1/BRCA2 gene mutation. (2) A first- or second-degree relative with one or more of the following conditions: (1) Age at onset ≤ 45 years; (2) Age at onset ≤ 50 years and one consanguineous relative with breast cancer who is also ≤ 50 years of age and/or one or more consanguineous relatives with ovarian epithelial cancer/fallopian tube cancer/primary peritoneal cancer of any age; (3) A single individual with 2 primary breast cancers and a first primary breast cancer. (3) A single individual with 2 primary breast cancers and age of first presentation ≤ 50 years; (4) Two or more consanguineous close relatives of any age with breast cancer and/or ovarian epithelial/fallopian tube/primary peritoneal cancer; (5) A consanguineous male close relative with breast cancer; (6) Combined past history of ovarian epithelial/fallopian tube/primary peritoneal cancer. (3) First or second degree consanguineous relative with ovarian epithelial cancer/ fallopian tube cancer/ primary peritoneal cancer. (4) Male breast cancer patient in a first or second degree consanguineous relative (5) Family history of: (1) First- or second-degree consanguineous relatives who meet any of the above criteria; (2) Third-degree consanguineous relatives with 2 or more patients with breast cancer (at least 1 with age ≤50 years) and/or ovarian epithelial cancer/fallopian tube cancer/primary peritoneal cancer.