AFP is a glycoprotein synthesized by the liver and yolk sac during embryonic stage, and its content in normal adult blood circulation is very small <20μg/L. AFP is the best marker for the diagnosis of primary liver cancer, and the diagnostic positivity rate is 60%-70%. AFP is the best marker for the diagnosis of primary hepatocellular carcinoma, with a positive rate of 60%-70%. If the serum AFP is >400μg/L for 4 weeks or 200-400μg/L for 8 weeks, the diagnosis of primary hepatocellular carcinoma can be made by combining with imaging. In patients with acute and chronic hepatitis and cirrhosis, the concentration of AFP in serum may be increased to varying degrees, and its level is often <300ug/L. Germinal tumors (testicular cancer, teratoma) may have increased AFP content. 2. Carcinoembryonic antigen (CEA) Liu Chengli, Department of Hepatobiliary Surgery, Air Force General Hospital Carcinoembryonic antigen is a glycoprotein embryonic antigen found in fetal and colon cancer tissues, and is a broad-spectrum tumor marker. The normal reference value of serum CEA is <5μg/L. The positive rates of CEA in malignant tumors are colon cancer (70%), gastric cancer (60%), pancreatic cancer (55%), lung cancer (50%), breast cancer (40%), ovarian cancer (30%) and uterine cancer (30%) in order. Some benign diseases such as rectal polyps, colitis, liver cirrhosis and lung diseases also have elevated CEA levels to varying degrees, but the degree of elevation and positivity rate are low. 3. Cancer antigen 125 (CA125) CA125 exists in epithelial ovarian cancer tissues and patients' serum, and is the most studied ovarian cancer marker. The sensitivity of CA125 for ovarian epithelial cancer can reach about 70%. Other non-ovarian malignancies (cervical cancer, uterine body cancer, endometrial cancer, pancreatic cancer, lung cancer, gastric cancer, colon/rectal cancer, breast cancer) also have a certain positive rate. Benign gynecological diseases (pelvic inflammatory disease, ovarian cysts, etc.) and early pregnancy may show varying degrees of elevated serum CA125 levels.4. Cancer antigen 15-3 (CA15-3) CA15-3 can be used as an adjuvant for breast cancer diagnosis, postoperative follow-up and as an indicator of metastatic recurrence. It has low sensitivity (60%) for early stage breast cancer, 80% sensitivity for advanced stage and high positive rate (80%) for metastatic breast cancer. Other malignant tumors also have a certain positive rate, such as: lung cancer, colon cancer, pancreatic cancer, ovarian cancer, cervical cancer, primary liver cancer, etc. 5.Glycan antigen 19-9 (CA19-9) CA19-9 is a glycan antigen associated with gastrointestinal tract cancer, usually distributed in normal fetal pancreas, gallbladder, liver, intestine and normal adult pancreatic and bile duct epithelium. The detection of serum CA19-9 can be used as an auxiliary diagnostic indicator for pancreatic cancer, gallbladder cancer and other malignant tumors, and is of great significance for monitoring changes in disease and recurrence. Serum CA19-9 levels are also elevated in patients with gastric, colon/rectal, liver, breast, ovarian and lung cancers to varying degrees. CA19-9 is also elevated to varying degrees in certain gastrointestinal inflammatory diseases, such as acute pancreatitis, cholecystitis, cholestatic cholangitis, hepatitis, cirrhosis, etc. CA50 is a marker for pancreatic and colorectal cancers and is the most commonly used glycoantigen tumor marker, as it is widely present in the pancreas, gallbladder, liver, stomach, colorectum, bladder and uterus. CA50 can be detected in various malignant tumors with different positive rates, with the first positive rate of 94.4% for pancreatic cancer and gallbladder cancer, followed by liver cancer (88%), ovarian and uterine cancer (88%) and malignant pleural fluid (80%). It can be used for the early diagnosis of pancreatic cancer, gallbladder cancer and other tumors, and also has high value for the diagnosis of liver cancer, gastric cancer, colorectal cancer and ovarian tumors. 7. glycoantigen 242 (CA242) CA242 is a glycolipid antigen associated with pancreatic cancer, gastric cancer and colorectal cancer. Serum CA242 has good sensitivity (80%) and specificity (90%) for the adjuvant diagnosis of pancreatic cancer and colorectal cancer. CA72-4 is one of the best tumor markers for the diagnosis of gastric cancer, with high specificity and sensitivity of 28-80%, and can monitor more than 70% of gastric cancers if combined with CA19-9 and CEA. CA72-4 level is significantly correlated with the stage of gastric cancer, and generally increases in the stage III-IV of gastric cancer, and the positive rate of CA72-4 is much higher than that of non-metastatic gastric cancer patients. CA72-4 levels can rapidly decrease to normal after surgery. In 70% of recurrent cases, CA72-4 concentrations are first elevated. The main advantage of CA72-4 over other markers is its high specificity for the differential diagnosis of benign lesions, with a detection rate of only 0.7% in a large number of patients with benign gastric disease. There is also a positive rate for colon/rectal cancer, pancreatic cancer, liver cancer, lung cancer, breast cancer, and ovarian cancer.9. Ferritin (SF) Elevated ferritin can be seen in the following tumors: acute leukemia, Hodgkin's disease, lung cancer, colon cancer, liver cancer, and prostate cancer. The detection of ferritin has diagnostic value for metastatic liver tumors. 76% of patients with liver metastases have ferritin levels higher than 400 μg/L. When the AFP measurement is low in the case of liver cancer, the ferritin measurement can be used to supplement it to improve the diagnostic rate. Ferritin is also elevated in cases of hyperpigmentation, inflammation, and hepatitis. The reason for the elevation may be due to cell necrosis, blocked erythropoiesis or increased synthesis in tumor tissue.10. Prostate-specific antigen (PSA) PSA is a glycoprotein synthesized by human prostate epithelial cells and secreted into the seminal plasma, PSA is mainly found in prostate tissue and does not exist in women, and the serum content of PSA in normal men is very low, with serum reference values <4 μg/L. PSA is organ-specific, but not tumor-specific. The positivity rate for the diagnosis of prostate cancer is 80%. The serum PSA level can also be elevated to varying degrees in benign prostate disease. Serum PSA measurement is a monitoring indicator for postoperative recurrence and metastasis of prostate cancer and for observing the efficacy of treatment. It is present in the blood in two forms: bound PSA and free PSA. The F-PSA/T-PSA ratio is an effective indicator to differentiate prostate cancer from benign prostate disease. It is an important indicator for prostate cancer diagnosis, staging, efficacy observation and prognosis. The PAP of prostatitis and prostate hyperplasia is also increased to some extent.12. β2-microglobulin (β2-MG) β2-microglobulin (β2-m) is expressed on the surface of most nucleated cells. It is mostly used clinically to diagnose lymphoproliferative diseases, such as leukemia, lymphoma and multiple myeloma. Its level correlates with the number of tumor cells, growth rate, prognosis and disease activity. In addition, it can be used to stage patients with myeloma according to this level. Serum β2-MG can be increased in renal failure, inflammation and various diseases. NSE is a tumor marker for small cell lung cancer (SCLC) with a positive diagnostic rate of 91%. It helps in the differential diagnosis of small cell lung cancer and non-small cell lung cancer (NSCLC). It is also valuable for the observation of the efficacy and recurrence monitoring of small cell lung cancer. Serum NSE concentration can be significantly increased in neuroblastoma, neuroendocrine cell tumor.14. Cytokeratin 19 (Cyfra21-1) Cyfra21-1 is a soluble fragment of cytokeratin-19.Cyfra21-1 is a preferred marker for non-small cell lung cancer, especially squamous lung cancer. Cyfra21-1 is also a good adjuvant diagnostic and therapeutic monitor for breast, bladder and ovarian cancers. 15. Squamous cell carcinoma antigen (SCCA) Squamous cell carcinoma antigen (SCCA) is a tumor-associated antigen TA-4 extracted from cervical squamous epithelial cell carcinoma tissue. SCCA is a tumor marker for squamous carcinoma, and is used in cervical cancer, squamous lung cancer, esophageal cancer, head and neck cancer, adjuvant diagnosis of bladder cancer, treatment observation and recurrence monitoring.16. Nuclear Matrix Protein-22 (NMP-22) NMP- 22 (NuclearMatrixProtein-22) is a component of the cytoskeleton. It is closely related to cellular DNA replication, RNA synthesis, regulation of gene expression, and hormone binding. In bladder cancer, a large number of tumor cells apoptosis and release NMP22 into the urine, and the urinary NMP22 can be increased 25-fold. Using 10kU/mL as the threshold value, the sensitivity for bladder cancer diagnosis is 70% and the specificity is 78.5%. The sensitivity for the diagnosis of invasive bladder cancer is 100%.17. α-L-amyloidase (AFU) AFU is another sensitive and specific new marker for the detection of primary hepatocellular liver cancer. Serum AFU activity is significantly higher in patients with primary hepatocellular carcinoma than in other types of diseases (including benign and malignant tumors). However, it is worth mentioning that there is some overlap between serum AFU activity measurements in some metastatic hepatocellular carcinomas, lung, breast, ovarian or uterine cancers, and even in some non-neoplastic diseases such as cirrhosis, chronic hepatitis and gastrointestinal bleeding, which are mildly elevated. The use of AFU should be measured simultaneously with AFP to improve the diagnosis of primary hepatocellular carcinoma and has a good complementary effect.