(A) How does breast cancer develop? The process of breast cancer can be divided into two stages. The first stage is the “initiation stage”, which refers to the transformation of normal human cells under the action of certain factors (initiating factors). The transformed cells do not necessarily become cancer cells, but only when they are repeatedly affected by one or more factors with cancer-promoting effects (such as environmental factors, emotions and stress, irregular life, etc.), the second stage is called cancer-promoting or promoting stage. The normal epithelial cells of breast will gradually develop atypical proliferation and then cancer after repeated contact with some cancer-promoting factors for a longer period of time after the initiation stage. In the early stage, it is called carcinoma in situ. Later on, it continues to grow and starts to break through the basement membrane of the ductal epithelium and infiltrate into the interstitial cells, and as the cancer cells extensively infiltrate into the interstitial cells, the cancerous tissue and interstitial cells mix with each other and metastasize to the lymph nodes and blood vessels. However, under normal circumstances, our body has a powerful cancer suppression system. In a normal cell, there is an oncogene present in addition to the oncogenes. The normal oncogenes are monitored by the oncogenes, and it is very difficult for it to succeed in its malignant behavior. Therefore, although we encounter some cancer-causing factors every day, the vast majority of people do not develop cancer. However, when the body’s immune supervision is weakened and the oncogenes inside its cells are activated and mutated genes are formed, the cell will have abnormal behavior and it will continuously fission and expand endlessly, which is cancer. Because the breast gland is easily stimulated by adverse factors, such as emotional factors and female hormones, it becomes a “favored” place for cancer cells. (2) What are the signs of breast cancer? If you find a nodule or lump in your breast that is not painful or red, you should consult a specialist for examination. 2. Rapid enlargement of the breast within a few weeks with skin redness and swelling, but not inflammation, should be alerted to inflammatory breast cancer. 3.Increased nipple or nipple pointing change should be suspected to be caused by breast cancer pulling and invading breast ducts. 4. Ulceration or eczema on the nipple or areola should be alerted as “eczema-like” breast cancer. 5.The skin of the breast sinks inward, forming a “dimple sign”, which is caused by cancer cells invading the breast ligaments and the ligaments losing elasticity. 6. The orange peel sign of breast skin is due to the blockage of subcutaneous lymphatic vessels by cancer cells, resulting in edema of the skin. 7.The repeated occurrence of bloody nipple overflow, which refers to the phenomenon of automatic or passive appearance of liquid from nipples during non-lactation period. 8.If an axillary lump is found, especially an enlarged lymph node in one side of the axilla, a specialist should be consulted to rule out the possibility of axillary lymph node metastasis due to breast cancer. 9.Although no lump can be felt, but ultrasound examination reveals nodules in the breast with irregular edges and high blood flow index; or mammography reveals focal sediment-like calcification, which is also a sign of early breast cancer.