Breast lumps are the most common clinical manifestation of breast cancer patients, and 80% of breast cancer patients present with breast lumps as the main complaint. However, with the popularization of tumor knowledge and cancer screening, the proportion of breast lumps found by patients during self-examination and routine check-ups by doctors is gradually increasing. However, it does not necessarily mean that breast lumps are breast cancer, and not all breast cancers appear in the form of breast lumps. (1) Breast lumps are mostly painless lumps, usually found in the area between the outer part of the breast and the armpit (i.e. the upper outer quadrant), and are usually irregular spherical lumps with unclear borders and hard texture that cannot be easily moved when pushed. Since breast cancer is mostly a painless lump, breast lumps without pain are the main reason for delayed diagnosis of breast cancer in many women. Therefore, if you find a lump at home, you should go to the hospital and get expert advice. (2) Nipple changes Very often, there is fluid overflowing from the nipple, which can be bloody, purulent, watery, milky, etc. Especially, special attention should be paid when there is bloody fluid flowing automatically. However, long-term stimulation, such as repeated sucking of the nipple or long-term repeated breast rubbing can trigger nipple overflow. Sometimes there are also manifestations such as nipple flaking, erosion, and indentation. For example, eczema-like carcinoma of the nipple, often with itching, nipple flaking often accompanied by secretions and crust, remove the scab and see a bright red erosion surface, which does not heal over time. The vesicle gradually spreads to the surrounding area and can involve the areola and even most of the skin of the breast, in addition to the nipple. (3) Skin manifestation of breast The early stage of breast cancer may not show obvious manifestation. As the breast cancer continues to develop, the skin on the surface of the tumor will be depressed and the appearance is like orange peel. As the skin on the surface of the breast is thin, superficial veins are visible underneath it that are varicose. Some breast cancers, such as inflammatory breast cancer, will show redness and swelling of the breast skin and local skin temperature increase, and as the disease continues to progress, local skin edema will appear. In advanced cases, the skin may become ulcerated or form scattered hard nodes. (4) Lymphatic metastasis The most common site of breast cancer metastasis is the ipsilateral axillary lymph nodes, followed by the ipsilateral internal breast lymph nodes. In advanced stage, ipsilateral or contralateral supraclavicular lymph nodes may be involved. Lymph nodes in the contralateral breast may also be metastasized in advanced stages. Breast cancer is very likely to metastasize to other parts of the body.