Epidemiology Epidemiological surveys have found that 5% to 10% of breast cancers are familial. If one close relative has breast cancer, the risk of developing the disease increases 1.5 to 3 times; if two close relatives have breast cancer, the prevalence will increase 7 times. The younger the age of onset of the disease, the greater the risk of breast cancer among relatives. This can prove that breast cancer is hereditary and there is a clear tendency of family inheritance. Lv Wenqiang, Department of Surgery, Jieyang People’s Hospital Modern medicine proves that breast cancer has a family history, also known as familial cancer. It has been clinically proven that there are maternal grandmothers or mothers or sisters in the families of women with breast cancer who have breast cancer, which is consistent with autosomal dominant inheritance, a site-specific type of inheritance, and the tumor that their family members are susceptible to is breast cancer. Patients with breast enlargement or fibroids should be alerted and treated aggressively here to prevent the development of breast cancer and the vicious cycle of inheritance to oneself and then to one’s children, as breast cancer is susceptible to genetic mutations in families with high risk of breast cancer. Breast cancer is the result of genetic mutation of breast gland epithelial cells under the action of various carcinogenic factors, resulting in uncontrolled cell proliferation. Due to the altered biological behavior of the cancer cells, it shows a disorderly and unrestricted malignant proliferation. Its histological manifestation is the infinite proliferation and disorderly crowding of a large number of infantile cancer cells, which squeezes and damages the surrounding normal tissues and destroys the normal tissue structure of the breast. Since the 20th century, the incidence of breast cancer has been on the rise worldwide. In Europe and North America, it is the first and second most common malignant tumor in women. In China, there were 200,000 breast cancer patients in the early 1990s, with about 50,000 new cases each year. The incidence rate of breast cancer increases with age in women. It is rare before the first menstruation and rare before the age of 20, but the incidence rate increases rapidly after the age of 20, and is higher from 45 to 50, but is relatively flat. Gradually increase until old age always maintain an upward trend. 2 Genetic factors: The risk of breast cancer is 2 to 3 times higher than normal for women with a history of first-degree direct family history of breast cancer 3 Other breast diseases 4 Age of menarche: The risk of menarche is 2.2 times higher for those who have menarche earlier than 13 years old than those who are older than 17 years old 5 Age of menopause: The risk of menopause increases for those who are older than 55 years old than those who are younger than 45 years old 6 Age of first pregnancy: The risk increases with the delay of the age of first birth 7 Postmenopausal estrogen supplementation: Long-term use of estrogen during menopause may increase the risk of breast cancer 8 Oral contraceptives 9 Food: High intake of fat, in particular, may increase the risk of breast cancer 10 Alcohol consumption 11 Weight gain may be an important risk factor for breast cancer in postmenopausal women 12 Long-term smoking 13 Ovarian function The breast is regulated by ovarian hormones. Estrogen is the basic stimulator of breast development and is one of the prerequisites for the development of breast tumors. It is believed that the abnormal increase of estrone and estradiol and the lack of estriol is one of the causes of breast tumor, which has been supported by clinical examination and proved by animal experiments. Moreover, male breast tumor patients are rare, about 1% of female patients, which may be related to the absence of ovarian hormones in men.