The so-called molecular targeted therapy means that the drugs entering the body will specifically select the oncogenic sites at the molecular level to combine and cause the specific death of tumor cells, without affecting the normal tissue cells around the tumor. Therefore, molecular targeted therapy is also called “biological missile”, which generally only has an inhibitory effect on the tumor, but has less side effects on normal tissues, and is characterized by high efficiency and low toxicity. Targeted therapy for breast cancer Does targeted therapy belong to chemotherapy? Targeted therapy is essentially a kind of biological therapy, not chemotherapy, and there is an essential difference between the two. Traditionally, chemotherapy drugs mainly refer to cytotoxic drugs, which are chemical substances with killing effect on tumor cells, but also toxic to many normal tissue cells that also divide vigorously, such as: white blood cells, platelets, gastrointestinal mucosa, hair follicles, etc. Therefore, chemotherapy often causes some related side effects, such as: decrease in white blood cells, decrease in platelets, nausea and vomiting, hair loss, etc. Targeted therapy drugs theoretically target only tumor cells and have no effect or less effect on normal tissues, so they tend not to have chemotherapy-related side effects. What are the types of molecular targeted therapeutic drugs used in clinical practice? According to the target and nature of the drugs, the main molecular targeted therapy drugs can be divided into the following categories: 1. small molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, such as gefitinib and erlotinib; 2. anti-EGFR monoclonal antibodies, such as cetuximab; 3. anti-proto-oncogene human epidermal growth factor receptor 2 monoclonal antibodies, such as trastuzumab; 4. 4, anti-vascular endothelial growth factor receptor (VEGFR) inhibitors, such as bevacizumab; 5, mammalian rapamycin target protein kinase inhibitor, everolimus; 6, anti-CD20 monoclonal antibodies, such as rituximab, etc. What is HER-2? How is it detected and interpreted? The Chinese name for HER-2 (C-erbB2) is human epidermal growth factor receptor-2. The main methods currently used to detect HER-2 are immunohistochemistry (IHC) and fluorescence immunohybridization (FISH), both of which have their advantages and disadvantages. the IHC method detects HER-2 protein with specific antibodies, while the FISH method detects the amplification of the HER-2 gene. the IHC test The IHC method is simple, popular and inexpensive, but the results are more influenced by the specimen, reagents and technique, and sometimes prone to false results. the FISH method is complex, expensive and not available in many hospitals, but the results are more accurate and objective. In general, all breast cancer specimens are tested for HER-2 by IHC method and the results are classified as -, +, ++, ++++, etc. – and + are usually defined as HER-2 negative, ++++ is defined as HER-2 positive (overexpression), while for +++, HER-2 may be negative or positive and needs to be further verified by FISH method. And the results of FISH method can be quantified and divided into no amplification and amplification, with no amplification patients defined as HER-2 negative and amplification patients defined as HER-2 positive.