The majority of malignant tumors of the breast originate from the epithelial tissue of the breast (breast cancer), while a few can originate from various non-epithelial tissues of the breast (various sarcomas), and occasionally mixed carcinosarcomas can be seen. Breast cancer is the main malignant tumor that affects women’s health, with approximately 1.2 million women developing and 500,000 women dying from breast cancer worldwide each year. Breast cancer is a common malignant tumor in women. In developed countries such as Western Europe and North America, the incidence of breast cancer accounts for the first place of female malignant tumors. Although China is a low incidence area for breast cancer, its incidence rate is increasing year by year, especially Shanghai, Beijing, Tianjin and coastal areas are the high incidence areas for breast cancer in China. The incidence is 23/100,000, accounting for 7-10% of all kinds of malignant tumors in the body. The mortality rate of breast cancer is increasing by 3% per year, surpassing that of lung cancer in urban areas and becoming the fastest growing cancer in the past 10 years. From 1991 to 2000 alone, the mortality rate of breast cancer among urban women increased by 38.9%, which has become a common disease that seriously threatens women’s health in China. The earliest manifestation of breast cancer is the appearance of a single, painless and progressive small lump in the affected breast. The most common lumps are located in the outer upper quadrant, followed by the nipple, areola area and inner upper quadrant. The lumps are often found unintentionally (e.g., bathing, dressing) because there are no conscious symptoms. A small number of patients may have varying degrees of tenderness or irritation and nipple discharge. The lump may grow rapidly and invade the surrounding tissues causing a change in the shape of the breast and a series of signs. Earlier signs may be detected by imaging. The key to breast cancer diagnosis and treatment is early detection, early diagnosis and early treatment. Self-examination is the most effective way to detect early breast cancer. Women of childbearing age or above should conduct a detailed self-examination of their entire breast (including both armpits) at least once a month after menstruation. Once you find any suspicious situation, you should go to a breast specialist immediately and your doctor will give you the appropriate examinations: mammography can detect early tumor lesions that are not yet clinically palpable; smear for nipple overflow and ductoscopy is a way to detect breast cancer at an early stage; fine-needle aspiration cytology or Bard and McMurdo histology examination of the suspicious part of the breast; ultrasound examination of the breast can complement the X-ray examination. Ultrasound examination of the breast, which is complementary to X-ray examination, can detect breast lumps smaller than 1 cm and can also understand the blood flow around the tumor; for suspicious lesions of the breast, including severe breast hyperplasia, surgical excision and pathological biopsy should be actively performed.