The breast is a target organ for many endocrine hormones, among which estrogen has a clear relationship with the development of breast cancer. In China, breast cancer is mainly a disease of middle-aged and elderly people, with the main age of onset between 35 and 55 years old. Current research shows that the occurrence of human tumors may be caused by a combination of factors over a long period of time. Epidemiological studies have revealed that breast cancer patients have the following high-risk factors: 1. Menstrual status: The earlier the menarche, the greater the chance of developing breast cancer in the future. Those who have menarche ≥ 14 years old or above have 20% less chance of breast cancer than those under 12 years old. The later the menopause, the greater the chance of developing breast cancer. Those who have menopause at the age of 55 or above have one time more chance of getting breast cancer than those who have menopause at the age of 50 or below. 2. Childbirth status: Those who have their first child before the age of 18 have 4 times less chance of breast cancer than those who have their first child almost 30 years old. It is generally believed that women who have given birth to one child have less chance of breast cancer than those who have never given birth. 3. History of pre-cancerous breast lesions: Those who have lobular carcinoma in situ or non-invasive ductal carcinoma have a significantly higher chance of developing wet breast cancer. Clinical and statistical data show that cystic breast disease may be a cancer-causing factor, and among women with cystic breast disease, the chance of developing breast cancer is 2.5 to 4 times greater than that of the average woman. If cystic hyperplasia is also accompanied by active epithelial cell proliferation, the incidence of breast cancer is 4 to 7 times greater than normal. Intraductal papillomas have the potential to become cancerous. Rarely, papillomatosis is also a precancerous lesion. 4.Personal history of breast cancer: after treatment of breast cancer on one side, the chance of breast field change on the opposite side is 5 times greater than the chance of first breast cancer in general women, especially those with pathological diagnosis of lobular carcinoma in situ or multifocal carcinoma. 5. Family history of breast cancer, especially if the patient’s mother or sister had breast cancer, or if the patient had premenopausal onset or bilateral breast cancer. 6. Excessive obesity: girls are prone to early sexual maturity, which will lay the foundation for breast cancer in the future. The incidence of breast cancer in obese people is 3.45 times higher than that of non-obese people, because excessive fat accumulation increases the production of estrogen, which stimulates breast tissue and, over time, causes breast cancer. 7. Long-term heavy use of exogenous estrogen: Long-term and heavy use of estrogen-containing health products, especially postmenopausal women who use estrogen replacement products or synthetic estrogen drugs for a long time, will significantly increase their risk of breast cancer. 8. Too many abortions: Normal natural abortion does not increase the risk of breast cancer, while repeated abortions, or multiple abortions before the age of 18, are likely to cause breast diseases and increase the risk of breast cancer. 9. Bad habits: People who prefer smoking, drinking, irregular diet and fried food have a higher rate of disease. 10. Depression: Women who are prone to depression such as nervousness and anxiety, loneliness and depression, sadness and sorrow, bitterness and disappointment, impatience and irritation, etc., are subject to long-term adverse emotional stimulation, disruption of body rhythm, dysfunction of neuroendocrine system, which in turn leads to imbalance of internal environment and decrease of immunity, which can reduce thymus generation and release of thymosin, the monitoring ability of lymphocytes and macrophages on mutated cells in the body and The ability of lymphocytes and macrophages to monitor and phagocytose mutated cells in the body decreases, and cancer is likely to occur. 11. X-ray exposure: Epidemiological studies have found an increased incidence of breast cancer among survivors of long-term exposure to X-rays, such as in Japan after the atomic bombings of Hiroshima and Nagasaki, so it is important to prevent excessive exposure to radiation, especially in young unmarried women. It is important to note that having one or several risk factors does not necessarily mean that one will or is susceptible to breast cancer, but simply that the patient is at statistically greater risk than the general population, but the patient’s risk of getting breast cancer may still be quite small. We should not neglect routine breast examinations because of the low incidence of breast cancer because early breast cancer can be detected through routine examinations, and the combination of mammography and mammography can correctly diagnose more than 95% of breast diseases. For women older than 35 years old, especially those with high-risk factors, we recommend a mammogram once every six months and a mammogram once a year for early detection, early diagnosis, early treatment and early recovery of breast diseases.