In the research and clinical practice of tumor, early detection, early diagnosis and early treatment are key. Tumor Marker TM is of great practical value in tumor screening, diagnosis, judgment of prognosis and regression, evaluation of therapeutic efficacy and follow-up observation of high-risk groups. Tumor markers mainly refer to a class of bioactive substances that are synthesized and secreted by tumor cells into body fluids or tissues during the occurrence and development of malignant tumors, or produced abnormally by shrinking hosts in response to new biological reactions in vivo, with significantly higher content in body fluids or tissues. With the development of molecular biology technology, it is found that the change of gene structure or function and the abnormal expression of gene products with certain biological functions are closely related to the occurrence and development of tumor, so oncogenes, oncogenes and their products also belong to tumor markers. There are many kinds of tumor markers used for clinical diagnosis, which can be divided into: carcinoembryonic antigens, glycoprotein antigens, enzymes, hormones, oncogenes and tumor-related viruses. AFP is a functional protein in embryonic stage, produced by yolk sac and embryonic liver, and the content of cord blood is 1000-5000μg/L, which decreases to adult level (less than 20μg/L) within 1 year after birth. About 70% or more of patients with primary hepatocellular carcinoma have AFP above 400 μg/L, which mostly rises gradually, but there are also patients with AFP not higher than 400 μg/L or even at normal levels. Pregnancy, active liver disease, germinal gland embryonic tumors, etc. may also be elevated. 2.Cancer embryonic antigen (CEA) CEA is an acidic glycoprotein that is synthesized in the small intestine, liver and pancreas during the embryonic period. CEA was initially considered a marker for colon cancer (elevated in 60-90% of patients), but later it was found to be elevated in pancreatic cancer (80%), gastric cancer (60%), and other cancers. CEA was initially thought to be a marker for colon cancer (elevated in 60%-90% of patients), but was later found to be highly expressed in pancreatic cancer (80%), gastric cancer (60%), lung cancer (75%) and breast cancer (60%). It can also be mildly elevated in some patients with lung cancer. 3 .CA125 was initially thought to be specific for ovarian cancer, but in-depth studies have revealed that it is also a broad-spectrum marker. The normal value is defined as 35U/ml. 80% of ovarian cancers, 58% of pancreatic cancers, 32% of lung cancers, and other cancers such as breast cancer and liver cancer can also have different degrees of elevation. Endometritis, acute pancreatitis, peritonitis, hepatitis, cirrhosis ascites, tuberculosis and other benign diseases can also be elevated. CAl5-3 is a variant of glycoprotein on the epithelial surface of breast cells and is a marker of breast cancer, with a normal level of <30 U/ml. This marker is also broad-spectrum and can be elevated in other tumors such as liver cancer, lung cancer, ovarian cancer, stomach cancer, intestinal cancer and pancreatic cancer. 5 .CA19-9 CAl9-9 is a glycoprotein component of mucin-like protein, which is related to Lewis blood group components. The normal value in serum is <37U/mL (>95%), which is a more reliable marker of pancreatic cancer and is elevated in 79% of pancreatic cancers. However, abnormal elevation can also be seen in a variety of other tumors, such as 67% of biliary tract cancer, gallbladder cancer, 62% of gastric cancer, some colon cancer, liver cancer, lung cancer, breast cancer, etc. are also elevated. A small number of benign lesions and normal people can also be elevated. CA72-4 is a kind of high molecular weight glycoprotein, the content of which is <6U/ml in normal human serum, and can be abnormally increased in various gastrointestinal tumors and ovarian cancer. The specificity of detection for gastric cancer is high, and >6U/ml is the threshold value. Only <1% of benign gastric disease is elevated, while the proportion of elevated gastric cancer can reach 42.6%, and if tested simultaneously with CAl9-9, the positivity rate can reach 56%. CA242 is a mucin-type glycoantigen, which can be used as a good tumor marker for pancreatic cancer and colon cancer. Its sensitivity is similar to CA19-9, but its specificity and diagnostic efficiency are better than CA19-9. 8.Squamous cell associated antigen (SCC) is purified from cervical cancer cells, which is a good tumor marker for cervical cancer. It is a good tumor marker for cervical cancer, with normal serum level <2μg/L. Abnormal elevation can be seen in squamous cervical cancer and 21% of cervical adenocarcinoma. There is a high positive rate for squamous lung cancer. SCC is an important marker for squamous epithelial carcinoma. Cytokeratin 19 (CYFRA21-1) is an intermediate filament of cell body, which can be divided into 20 different types according to its molecular weight and isoelectric point, among which cytokeratin 19 is of great value in lung cancer diagnosis. Histologically, the sensitivity of squamous carcinoma (76.5%) was higher than that of adenocarcinoma (47.8%), and also higher than the diagnostic rate of SCC for both. Cytokeratin 19 in combination with CEA has been used to diagnose non-small cell lung cancer with a compliance rate of 78%. 10 , β2-microglobulin is expressed on the surface of most nucleated cells and is a molecular weight 11,800 chain of HLA-A, B and -C antigens. It is mostly used clinically to confirm lymphoproliferative diseases, such as leukemia, lymphoma and multiple myeloma. Its level is related to the number of tumor cells, growth rate, prognosis and disease activity. 11 , Ferritin is an iron-binding protein that exists in various tissues and increases in pathological state when released into the blood. It has different degrees of positive rate in the blood of many cancer patients, and the positive rate in liver cancer patients is over 70%, so it can assist in the diagnosis of liver cancer. However, it is not a tumor-specific marker and may be elevated in fever, hepatitis, cirrhosis, obstructive jaundice, aplastic anemia and some hemolytic diseases. PSA is a large molecule glycoprotein produced by prostate epithelial cells, which has high tissue and organ specificity. PSA in normal human serum is <4μg/L, but tends to increase with age. ＜It is generally lower than 4.0 μg/L in people <50 years old, 4.4 μg/L in people 50-55 years old, 6.8 μg/L in people 60-69 years old, and up to 7.7 μg/L in people >70 years old, and an abnormal increase indicates the possibility of prostate cancer. The threshold value of >4μg/L is 63%-70% positive for early prostate cancer, and the total positive rate can be 69-92.5%. 13, Neurogen-specific enolase (NSE) Serum NSE is a specific marker for neuroendocrine tumors, such as neuroblastoma, medullary thyroid cancer and small cell lung cancer (72% elevated). Currently, NSE has been used as one of the important markers for small cell lung cancer. NSE may also be elevated in the event of hemolysis during blood sampling. 14, Chorionic gonadotropin (HCG) is a glycoprotein hormone present in the placenta, the amount of which is 45,000. HCG is significantly elevated in patients with chorioepithelial carcinoma and in 60% of testicular tumors. HCG can be positive in the urine in ovarian, breast, cervical, endometrial, hepatocellular, and lung cancers. HCG can be elevated in the blood of some benign diseases such as peptic ulcer, enteritis and cirrhosis of the liver.