AFP is a glycoprotein synthesized by liver and yolk sac during embryonic period, and the content of AFP in normal adult’s blood circulation is <20μg/L. AFP is the best diagnostic marker for primary liver cancer, and the diagnostic positivity rate is 60%~70%. If serum AFP＞400μg/L lasts for 4 weeks, or 200~400μg/L lasts for 8 weeks, combined with imaging examination, the diagnosis of primary liver cancer can be made. In patients with acute and chronic hepatitis and cirrhosis, the concentration of AFP in serum can be elevated to different degrees, and its level is often <300ug/L. Reproductive embryonic tumors (testicular cancer, teratoma) can be seen to have elevated levels of AFP. Carcinoembryonic antigen (CEA) is a glycoprotein embryonic antigen found in fetal and colon cancer tissues, which belongs to broad-spectrum tumor markers. The normal reference value of serum CEA is <5μg/L. The positive rate of CEA in malignant tumors is colon cancer (70%), stomach cancer (60%), pancreatic cancer (55%), lung cancer (50%), breast cancer (40%), ovarian cancer (30%), uterine cancer (30%). Some benign diseases such as rectal polyps, colitis, liver cirrhosis, and lung disease also have different degrees of elevated CEA levels, but the degree of elevation and positive rate are low. 3. Carcinoma antigen 125 (CA125) CA125 exists in the epithelial ovarian cancer tissues and patients' serum, and it is the most researched ovarian cancer marker, which can be used for early screening, diagnosis, treatment, and prognosis. CA125 is the most studied ovarian cancer marker and is important in early screening, diagnosis, treatment and prognosis.The sensitivity of CA125 for epithelial ovarian cancer can reach about 70%. Other non-ovarian malignant tumors (cervical cancer, uterine cancer, endometrial cancer, pancreatic cancer, lung cancer, gastric cancer, colorectal cancer, breast cancer) also have a certain positive rate. Benign gynecological diseases (pelvic inflammatory disease, ovarian cysts, etc.) and early pregnancy may show different degrees of elevated serum CA125 levels. 4.Cancer antigen 15-3 (CA15-3) CA15-3 can be used as an indicator of breast cancer auxiliary diagnosis, postoperative follow-up and metastatic recurrence. The sensitivity of early breast cancer is low (60%), the sensitivity of late stage is 80%, and the positive rate of metastatic breast cancer is high (80%). Other malignant tumors also have a certain positive rate, such as: lung cancer, colon cancer, pancreatic cancer, ovarian cancer, uterine cervix cancer, primary liver cancer and so on. 5.Glycan antigen 19-9 (CA19-9) CA19-9 is a kind of glycan antigen associated with gastrointestinal tract cancer, usually distributed in normal fetal pancreas, gallbladder, liver, intestines and normal adult pancreas and bile duct epithelium. Detecting patients' serum CA19-9 can be used as an auxiliary diagnostic index for pancreatic cancer, gallbladder cancer and other malignant tumors, which is of great significance in monitoring the changes and recurrence of the disease. Serum CA19-9 levels are also elevated to different degrees in patients with gastric cancer, colorectal/rectal cancer, liver cancer, breast cancer, ovarian cancer and lung cancer. CA19-9 is also elevated to different degrees in certain inflammatory diseases of the digestive tract, such as acute pancreatitis, cholecystitis, cholestatic cholangitis, hepatitis, cirrhosis of the liver and so on. 6.Cancer antigen 50 (CA50) CA50 is a marker for pancreatic and colorectal cancer, and it is the most commonly used glycan antigen tumor marker, because of its wide presence in pancreas, gallbladder, liver, stomach, colorectum, bladder, uterus, its tumor recognition spectrum is wider than CA19-9, so it is a universal tumor marker-related antigen, not a tumor marker specifically referring to a certain organ. CA50 can be detected in a variety of malignant tumors with different positive rates, with pancreatic and gallbladder cancers leading the positive detection rate, accounting for 94.4%; others are liver cancer (88%), ovarian and uterine cancers (88%), and malignant pleural fluid (80%), etc. It can be used for pancreatic cancer, gallbladder cancer and other malignant tumors. It can be used in the early diagnosis of pancreatic cancer, gallbladder cancer and other tumors, and also has high value in the diagnosis of liver cancer, gastric cancer, colorectal cancer and ovarian tumor. 7, Glycolipid antigen 242 (CA242) CA242 is a glycolipid antigen related to pancreatic cancer, gastric cancer and colorectal cancer. Serum CA242 is used for auxiliary diagnosis of pancreatic cancer and colon cancer, with good sensitivity (80%) and specificity (90%). The level of serum CA242 can be elevated in patients with lung cancer, liver cancer and ovarian cancer. CA72-4 is one of the best tumor markers for diagnosing gastric cancer, with high specificity for gastric cancer, its sensitivity can reach 28-80%, and it can monitor more than 70% of gastric cancers if it is combined with CA19-9 and CEA. CA72-4 level has obvious correlation with the stage of gastric cancer and generally increases in the III-IV stage of gastric cancer, and the positive rate of CA72-4 in gastric cancer with metastasis is much higher than that in non-metastatic patients. CA72-4 level can be rapidly decreased 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 very 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. Colon/rectal cancer, pancreatic cancer, liver cancer, lung cancer, breast cancer, ovarian cancer also have a certain positive rate. 9, ferritin (SF) ferritin elevation can be seen in the following tumors: acute leukemia, Hodgkin's disease, lung cancer, colon cancer, liver cancer and prostate cancer. Detecting ferritin has diagnostic value for liver metastatic tumors, 76% of patients with liver metastasis have ferritin level higher than 400μg/L. When liver cancer, AFP measurement value is low, available ferritin measurement value can be supplemented to improve the diagnostic rate. Ferritin is also elevated in hyperpigmentation, inflammation, and hepatitis. 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 seminal plasma. PSA mainly exists in prostate tissues, and it does not exist in females, and the content of PSA in the serum of normal males is very low, with a serum reference value of ＜4 μg/L; PSA is organ-specific but does not have tumor-specificity. The positive rate for diagnosing prostate cancer is 80%. Benign prostate disease can also be seen in serum PSA level increased to different degrees. Serum PSA measurement is a monitoring index for recurrence and metastasis of prostate cancer after surgery and observation of the efficacy of treatment. It exists in two forms in the blood: bound PSA and free PSAF-PSA/T-PSA ratio is an effective indicator to distinguish prostate cancer and benign prostate disease.F-PSA/T-PSA＞0.25 is mostly benign disease; F-PSA/T-PSA＜0.16 is highly suggestive of prostate cancer. Prostate acid phosphatase (PAP) is an important indicator for prostate cancer diagnosis, staging, therapeutic observation and prognosis. Prostatitis and prostate hyperplasia PAP is also increased to a certain degree. 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, this level is used to stage myeloma patients. Serum β2-MG can be elevated in renal failure, inflammation, and a variety of diseases. Therefore, serum β2-MG should be excluded due to certain inflammatory diseases or reduced glomerular filtration function. 13.Neuron specific enolase (NSE) NSE is an isoenzyme of enolase.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 of small cell lung cancer and the monitoring of recurrence. Neuroblastoma, neuroendocrine cell tumor serum NSE concentration can be significantly increased. 14, Cytokeratin 19 (Cyfra21-1) Cyfra21-1 is a soluble fragment of cytokeratin-19, which is the first choice of marker for non-small cell lung cancer, especially squamous lung cancer. Combined with CEA and NSE, Cyfra21-1 is valuable for differential diagnosis and disease monitoring of lung cancer, and it is also a good auxiliary diagnostic and therapeutic monitoring index for breast cancer, bladder cancer and ovarian cancer. 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, and the serum content of normal human is less than 2.5 μg/L. It is a tumor marker of squamous carcinoma, and it is suitable for the auxiliary diagnosis, therapeutic observation, and recurrence monitoring of cervical carcinoma, squamous carcinoma of the lung, esophageal carcinoma, head and neck carcinoma, and bladder carcinoma. 16.Nuclear Matrix Protein-22 (NMP-22) NMP-22 (NuclearMatrixProtein-22) is a component of cellular nuclear skeleton. It is closely related to cellular DNA replication, RNA synthesis, gene expression regulation and hormone binding. In bladder cancer, a large number of tumor cells apoptosis and release NMP22 into the urine, and the urinary NMP22 can increase 25 times. With 10kU/mL as the critical value, the sensitivity for bladder cancer diagnosis is 70% and the specificity is 78.5%. The sensitivity for diagnosis of invasive bladder cancer is 100%. 17.Alpha-L-fucosidase（AFU） AFU is another sensitive and specific new marker for primary hepatocellular carcinoma. The activity of serum AFU in patients with primary hepatocellular carcinoma is significantly higher than that in other kinds of diseases (including benign and malignant tumors). The dynamic curve of serum AFU activity is of great significance in determining the therapeutic effect of hepatocellular carcinoma, estimating the prognosis and predicting the recurrence, and it is even better than AFP, but it is worthwhile to point out that there is some overlap of the activity of serum AFU in some metastatic hepatocellular carcinomas, lung carcinomas, breast carcinomas, ovarian carcinomas or uterine carcinomas, and it is also mildly elevated in some non-tumor diseases, such as cirrhosis of the liver, chronic hepatitis, and gastrointestinal bleeding. , AFU should be measured at the same time as AFP when using AFU to improve the diagnosis of primary liver cancer and have a better complementary effect. Tumor marker (TM) testing is of great significance, which is summarized as follows: I. Tumor screening Tumor screening is to look for suspects from asymptomatic people. Tumor marker test is an effective method for initial screening of tumors. Tumor marker test is an effective method for initial screening of tumors. It is often used for screening of high-risk groups. AFP: screening for primary liver cancer. PSA: Screening for prostate cancer in men over 50 years old. High-risk HPV: screening for cervical cancer. CA125+Ultrasound: Ovarian cancer screening for women over 50 years old. Abnormally elevated tumor markers without obvious symptoms and signs need to be reviewed and followed up. If it is persistently elevated, the diagnosis should be confirmed in time. Diagnosis Auxiliary diagnosis: The specificity of tumor markers is not strong enough to confirm the diagnosis of tumor solely based on tumor markers, but it can provide clues for further diagnosis. Differential diagnosis: Ben-Chou protein, AFP, HCG, PSA, etc. have characteristic cancer spectrum. Cannot localize the diagnosis: tumor markers lack tissue and organ specificity. Dynamic observation: progressive elevation of tumor markers has clear diagnostic significance; elevation of markers in benign diseases is transient; elevation of markers in malignant tumors is persistent. Monitoring the condition and therapeutic effect Monitoring the therapeutic effect and recurrence and metastasis is the most important clinical application of tumor markers. After surgery, chemotherapy or radiotherapy, there is a good correlation between the rise and fall of the content of specific tumor markers and the therapeutic efficacy, and the dynamic observation can reflect the recurrence and metastasis of the tumor.