The individualized treatment of tumors depends on the understanding of the nature of the disease, and breast cancer is a highly heterogeneous group of diseases at the molecular level, and the traditional pathological staging is no longer adequate and sufficient for the understanding of the nature of the disease. Breast cancer is classified into 5 different subtypes at the molecular level. These 5 types are as follows: 1. LuminalA: The most common molecular subtype of breast cancer with an incidence of 40-60%. ER and/or PR+, Her-2-, Ki-67 low expression, best prognosis. Endocrine therapy has the best outcome. Endocrine therapy (± chemotherapy) is often used. Premenopausal often choose triamcinolone acetonide, pharmacological depot drug Norelide, postmenopausal often choose aromatase inhibitors such as anastrozole, letrozole, etc. 2.LuminalB type: luminalB type is 8%, ER and/or PR+, Her-2+, endocrine therapy is still effective and has a better prognosis. luminalB breast cancer is less responsive to tamoxifen than luminalA type due to positive Her-2 expression, but endocrine therapy with other mechanisms of action is still effective instead. Treatment is often done with chemotherapy + endocrine therapy + targeted therapy. 3, Her-2 overexpression type: incidence rate of 17%, ER and/or PR-, Her-2+, endocrine ineffective, chemotherapy is more effective, can apply trastuzumab (Herceptin) targeted therapy, the type of higher malignancy, early recurrence of metastasis, poorer prognosis, and often drug resistance, and significantly affect the patient’s disease-free survival rate. 4, Basal-like type: incidence of 10%, ER and/or PR-, Her-2-, endocrine ineffective, good chemotherapy, with the worst prognosis for triple negative. Its metastases mostly occur in the viscera and central nervous system. Treatment options are chemotherapy. Among breast cancer patients receiving preoperative neoadjuvant chemotherapy, there is a high overall response rate and pathological remission rate, with 85% of patients showing clinical remission, of which 27% achieve pathological complete remission, which is significantly higher than luminal type breast cancer. Although it is sensitive to preoperative neoadjuvant chemotherapy and has a high pathological remission rate, it still has the worst prognosis among the molecular subtypes of breast cancer. 5. Normal-like type: the incidence is 10%-14%. This type is distributed among the first 4 types of breast cancer and accounts for a larger proportion of Basal-like breast cancer. The immunophenotype is ER-, HER2-, and basal epithelial molecular markers such as CK5/6, CK14, CK17, and EGFR-. Normal-like breast cancer gene expression is similar to that of normal breast tissue and adenofibroma, with high expression of basal epithelial and adipose tissue genes, and low expression of luminal epithelial cell-related genes.