The exact cause of breast cancer development is still unclear, but it is related to several factors. The relative risk of breast cancer increases 2.2 times when the age of menarche is less than 12 years old compared to more than 17 years old, and the risk of breast cancer doubles when the age of menopause is more than 55 years old compared to less than 45 years old; 2. The average age of the second generation of breast cancer patients is about 10 years lower than that of the general population, and the risk of breast cancer among sisters is three times higher than that of the general population. Unhealthy “high-calorie, high-fat” diet, which leads to a much higher incidence of breast cancer; 6. According to the survey, introversion, long-term mental depression and unhappy early life are important factors leading to cancer; 9. Young urban women face fierce competitive pressure and are in a state of long-term mental stress, which easily leads to emotional instability. Together, these mental factors and bad life and work styles can cause further damage to breasts; 10. Improper use of estrogen-containing related drugs or products (including health products, cosmetics, etc.); 11. Environmental pollution, pesticide carcinogens, etc.