1. Painless breast lumps, mostly found unintentionally or during screening. The lump has poorly defined borders, hard texture, uneven surface, little mobility or completely fixed, with skin adhesion and “dimple sign”, and enlarged lymph nodes can be found in the ipsilateral axilla. In late stage, lymphedema may appear on the skin of the breast, with “orange peel”-like changes and satellite nodules on the surrounding skin, and the lump may be ulcerated and have a foul odor. Color ultrasound is helpful to identify whether the lump is cystic or substantial. Breast cancer often appears as an irregular hypoechoic lump with abundant blood flow signal. It can be the first choice of examination. 3.Mammography can show the shadow of the mass with irregular shape and burr-like edge, sometimes irregularly distributed fine sand-like calcification points can be seen. 4.Infrared thermogram examination: some breast cancer masses often have increased blood vessels locally and the surface temperature of the masses is increased, which is used as a comprehensive diagnosis in clinical practice. 5.Transillumination method: Using cancer tissues to preferentially absorb near infrared rays and then present different color images of brownish gray, brown or black to assist clinical diagnosis. 6.Tumor marker measurement: such as carcinoembryonic antigen (CEA) measurement is used as an auxiliary diagnosis, especially for those with bone and visceral metastasis. In addition, serum prolactin, calcitonin, lactate dehydrogenase isoenzyme, etc. can be used as diagnostic reference. 7.Pathological diagnosis: This is the most reliable diagnostic method. There are preoperative papillary overflow smear cytology, mass fine needle aspiration cytology, intraoperative mass excision frozen section examination and postoperative paraffin section examination. 8. Chest X-ray and liver ultrasound are routinely performed to detect or exclude distant metastases. 9. When taking medical history, attention should be paid to the presence of breast cancer susceptibility factors, such as family history, early menarche (before the age of 12), late menopause (after the age of 55), unmarried at advanced age, childlessness or first birth after the age of 35, previous breast cancer on one side and certain pre-cancerous breast lesions.