Individualized treatment of breast cancer With the increasing research in molecular biology, the understanding of breast cancer has become more detailed. It has been found that breast cancer is not a single disease, but a disease composed of different subtypes. Individualized treatment of breast cancer based on molecular typing will help to improve the outcome of breast cancer treatment. Breast cancer staging: 1. Luminal (ductal) type A: refers to breast cancer estrogen receptor (ER) and/or progesterone receptor (PR) positive, Ki-67 less than 14%, and human epidermal growth factor receptor 2 (Her-2) negative. The PAM50 gene classification technique was used to determine the LuminalA type as an important criterion. Characteristics:This type generally develops relatively slowly, is sensitive to endocrine therapy but not to chemotherapy, and does not require targeted therapy. Except for a few patients with a high number of combined lymph node metastases, high nuclear grade, and high-risk factors such as vascular tumor emboli, who need to receive chemotherapy, it is generally recommended that endocrine therapy alone can be used. It was found that the 8.5-year distant recurrence-free survival (DRFS) rate for those with lymph node(-) treated with endocrine therapy alone was more than 95%, and the 8.5-year DRFS rate for those with low to moderate risk of lymph node(+) was more than 90%, suggesting that chemotherapy can be avoided in this group of patients. Prognosis and outcome prediction suggest that LuminalA type has the best prognosis. 2, Luminal (tubular) type B: Luminal type B is divided into 2 types, human epidermal growth factor receptor 2 (Her-2) negative type (ER and/or PR positive, Her-2 negative, Ki-67 greater than or equal to 14%) and Her-2 positive type (ER and/or PR positive, Her-2 positive, regardless of Ki-67 value). Characteristics: This type has a high proliferation rate, recurrence is most often seen within the first 5 years after diagnosis, the good sites of metastasis are bone and pleura, and chemotherapy and endocrine therapy are not effective. Her-2 negative type suggests endocrine therapy + or – chemotherapy; Her-2 positive type suggests chemotherapy + anti-Her-2 therapy + endocrine therapy. 3. Her-2 overexpression type (also called Her-2 positive type): ER and PR negative, Her-2 overexpression or proliferation. Features: This type is a specific subtype of breast cancer with poorer clinicobiological features. Patients can benefit from anthracycline-containing-based regimens, and the monoclonal antibody trastuzumab has shown its importance in adjuvant therapy. 4. Basal-like type (also known as triple-negative TNBC): ER and PR negative, Her-2 negative. Characteristics: There is an 80% overlap between “triple negative” breast cancer patients and “basal-like” breast cancer patients, but the former also contains some specific histological types, such as low-risk medullary carcinoma and adenoid cystic carcinoma. Basal keratin staining is helpful in determining the true “basal-like” tumor. This type of breast cancer has unique biological characteristics, is heterogeneous, lacks targets for endocrine therapy and anti-Her-2 therapy, is sensitive to chemotherapy but quickly becomes resistant to it, and develops distant metastases earlier (in the first 5 years after surgery), with a higher probability of brain metastases, lung metastases, liver metastases and other visceral metastases, and a lower probability of bone metastases. There is no optimal standard treatment plan, and some studies have shown that chemotherapy with GP regimens is more effective than conventional chemotherapy regimens, and the overall efficacy of targeted therapy is unsatisfactory. The NCCN guidelines for adjuvant therapy for this type of disease are as follows: 1. For PT1, PT2, PT3, PT0 or PN1mi axillary lymph node metastases less than or equal to 0.2M: do not consider chemotherapy for PT0 in tumor less than or equal to 0.5M microinfiltration, consider chemotherapy for PN1mi; for tumor 0.6-1.0M, consider adjuvant chemotherapy (Class 1 evidence); 2. . for tumors larger than 1 cm, adjuvant chemotherapy should be considered (category 1 evidence); positive lymph nodes (meaning 1 or more ipsilateral axillary lymph nodes with 1 or more metastases larger than 2 MM), adjuvant chemotherapy should be considered (category 1 evidence).