Breast cancer is a common and prevalent disease that poses a serious threat to women’s health, and the American Cancer Society recommends that all women over the age of 20 should have regular monthly breast self-tests. After regular breast cancer self-testing, you will know the normal status of your breasts. If you notice any change in the status of your breasts, you can immediately detect it and go to the hospital for further examination. Most of the tumors are detected by women themselves. In case you find tumor, roughness or change in shape of the breast, please seek medical attention immediately. Breast self-examination is simple and can be done when you wake up, go to bed, change clothes or take a shower. The first step is to face the mirror and observe the shape of the breasts, whether the nipples are at the same level, whether they are elevated, retracted or sunken, whether there is any abnormal discharge from the nipples and whether there is any change in the color of the areola. The third step is to raise both arms above the head and carefully observe whether there is any change in the shape and contour of both breasts; whether there is any abnormality in the skin of the breasts. Pay attention to the presence of redness, rash, superficial venous anger, skin folds, orange peel-like changes, etc. Palpation method: Take a lying position, raise the right arm above the head and put a small pillow under the right shoulder to make the right breast flat. Then put the four fingers of the left hand together and use the palm of the fingers to check for lumps or other changes in various parts of the breast. There are three methods of examination. The first is the clockwise loop inspection method, in which the four fingers are used to inspect the breast from the nipple in a circular fashion from the inside out; the second is the vertical strip inspection method, in which the four fingers are used to inspect the entire breast from the top down; and the third is the wedge inspection method, in which the four fingers are used to inspect the breast in a radial fashion from the nipple outward. Thirdly, the same method is used to examine the left breast cancer and compare the difference between the left and right breast. Finally, the nipple should be gently squeezed with the thumb and index finger, and if there is any discharge and it is transparent or bloody, it should be reported to the doctor in time. Even if you are found to have breast hyperplasia through self-examination and diagnosis, do not be nervous because hyperplasia is not equal to pre-cancer, but do not be paralyzed. If there are cystic hyperplasia, lumps and nodules, it may develop into breast cancer, although the incidence is not high, it should be diagnosed and treated as early as possible.