1.Dense and firm breasts: The epidemiologist of the Center for Disease Control in the United States, Truss, applied mammography to 567 women in a five-year study and found that the risk of breast cancer increases with the density of breast tissue. Therefore, women with overly firm breasts, especially those with some kind of hard lumps, should seek help from doctors and X-ray examinations as early as possible so that abnormalities can be detected in time and appropriate measures can be taken. 2, multiple abortions: After an abortion, the pregnancy is suddenly interrupted and the hormone levels in the body suddenly drop, forcing the newly developed mammary glands to suddenly stop growing, making the glandular vesicles smaller or even disappear, and the mammary glands recover. However, this recovery is usually incomplete and can cause breast lumps and pain, and can lead to breast disease. Repeated breast lesions can become an important cause of breast cancer. 3.Breast with nipple overflow: Non-breast nipple overflow, whose incidence of breast cancer increases with age, especially in women aged 40 years or above, has a higher risk of breast cancer when breast overflow occurs, especially bloody or plasma overflow. Male nipple overflow, regardless of its nature, should be alert to the occurrence of breast cancer. 4. Breasts of women who rarely or never breastfeed.