The exact cause of breast cancer is still not clear, but through research, it has been found that the following people are prone to breast cancer: 1. early menarche (less than 12 years old), the age of menarche >= 14 years old is 20% less than that of 12 years old; late menopause, the risk of breast cancer increases by 3% for every year of delay; 2. unmarried, not pregnant, not breastfeeding; 3. those who have suffered from breast cancer before; 4. If someone in the immediate family (mother, sister) has breast cancer, then the chance of breast cancer is higher; 5. Women who drink alcohol, eat too much sweets and animal fat, and are overweight after menopause; 6. The chance of cancer in the opposite breast is 5 to 7 times higher than normal, 8.