High risk groups and risk factors for breast cancer 1. age above 35 years old, especially older women with no marital history; 2. age above 30 years old if they have not given birth or given birth for the first time; 3. age of menarche less than 12 years old, or late age of menopause; 4. family history, history of benign tumors, history of breast hyperplasia; 5. long-term history of multiple or one high-dose X-ray irradiation, history of electronic radiation; 6. long-term mental depression or severe mental stimulation. In daily life, people with high incidence of breast cancer suffer from the long-term repeated stimulation of many of the above six related factors and receive an excessive amount of carcinogenic factors. By combining the above six high-risk groups, the following four risk factors can be summarized: (i) Endocrine factors Epidemiology shows that: age, menstruation, marriage, childbirth, breastfeeding and other conditions are closely related to the occurrence of breast cancer, indicating that the level and activity of endocrine hormones play an important role in the occurrence. (2) Genetic factors The risk of breast cancer in relatives of breast cancer patients is 4-9 times higher than that of the normal population, and the younger the relatives are, the higher the risk. (3) Clinical factors Previous history of benign breast diseases may increase the risk of breast cancer in the future, especially the risk of atypical hyperplasia among breast enlargement diseases is 4-6 times higher than that of normal population. (iv) Other factors Environmental, mental, obesity and high fat diet, ionizing radiation and chemicals are directly or indirectly related to the occurrence of breast cancer. Family history, history of benign tumors, history of breast enlargement.