1, limited thickening of breast or painless lump, hard texture, non-smooth edge, unclear border, poor mobility; 2, abnormal secretion from nipple, especially bloody; 3, breast skin depression, orange peel-like skin changes, redness, swelling, or ulceration; 4, change in shape of breast, loss of symmetry on both sides; 5, enlarged lymph nodes in armpit or adherence into a mass. Breast cancer is more likely to occur when the above danger signals appear, but it is important to go to a regular hospital for examination to prevent further progress and deterioration of the patient’s condition.