Breast cancer plagues many modern women and causes both physical and psychological damage to the patient. What are the factors for the development of breast cancer? How can we prevent the occurrence of breast cancer? Breast cancer incidence factors: 1. Genetic susceptibility: Clinical data from family history surveys show that the incidence of breast cancer with family history is higher than that without family history. Especially for those with bilateral breast cancer and those with younger age of onset, the risk of breast cancer in these women is 9 times higher than that in general women, which may be related to genetic factors that make them have susceptibility to breast cancer and lesion endogenous. Endocrine factors: endocrine disorders are one of the causes of breast cancer. Due to the abnormal stimulation of endocrine hormones in the breast for a long time, it leads to cancer of breast tissue, among which estrogen and luteinizing hormone are the two endocrine hormones most closely related to breast malignancy. This has been confirmed by many clinical, pathologists and physiologists. Viral factors: Viral particles can be transmitted through breastfeeding and lead to breast cancer, which has been confirmed through more animal experiments. 4.Other factors: low immune function against cancer and suppression of immune function of anti-cancer factors; as well as traumatic stimulation of breast and radiation damage, all of them are reported to be prone to breast cancer.