With the development of society, accelerated pace of life, increased pressure of life and environmental pollution and other factors, the incidence of tumor is getting higher and higher. The key to treat tumor is early prevention, early detection and early treatment, and many tumors can be cured by early detection. There are many methods for early screening of tumors, such as chest X-ray, B-ultrasound, CT, MRI, etc., but they are more costly or limited, while tumor marker examination is faster, easier and more economical. Tumor markers are substances produced by tumor cells themselves or by the body’s reaction to tumor cells during the process of tumor occurrence and proliferation, which reflect the existence and growth of tumor, including proteins, hormones, enzymes (isoenzymes) and oncogene products. Tumor markers in blood or body fluids can be used to detect tumors at an early stage in tumor screening, to observe the efficacy of tumor treatment and to judge the prognosis of patients. AFP is a glycoprotein synthesized in the liver and yolk sac during embryonic stage, and its content in the blood circulation of normal adults 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%. The positive rate is 60%-70%. The diagnosis of primary hepatocellular carcinoma can be made when serum AFP >400μg/L for 4 weeks or 200-400μg/L for 8 weeks is combined with imaging examination. In patients with acute and chronic hepatitis and cirrhosis, serum AFP concentration may be increased to different degrees, but the level is often less than 300ug/L. Reproductive embryonic tumors (testicular cancer, teratoma) may have increased AFP content. 2.Cancer embryonic antigen (CEA) is a glycoprotein embryonic antigen found in fetal and colon cancer tissues, which is a broad-spectrum tumor marker. The normal reference value of serum CEA is <5μg/L. The positive rate of CEA in malignant tumors is colon cancer (70%), gastric cancer (60%), pancreatic cancer (55%), lung cancer (50%), breast cancer (40%), ovarian cancer (30%) and uterine cancer (30%) in order. CEA is an adhesion molecule, which is an important marker of metastasis and recurrence of many tumors. 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 indicator for adjuvant diagnosis of breast cancer, postoperative follow-up and metastatic recurrence. It has low sensitivity (60%) for early stage breast cancer, 80% for late 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 cancer, usually distributed in normal fetal pancreas, gallbladder, liver, intestine and normal adult pancreatic and bile duct epithelium. Testing patients' 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 in monitoring changes in disease and recurrence. Serum CA19-9 levels are also elevated to varying degrees in patients with gastric cancer, colon/rectal cancer, liver cancer, breast cancer, ovarian cancer, lung cancer, etc. Certain inflammatory diseases of the gastrointestinal tract also have different degrees of elevated CA19-9, such as: acute pancreatitis, cholecystitis, cholestatic cholangitis, hepatitis, cirrhosis, etc. CA50 is a marker of pancreatic and colorectal cancer and is the most commonly used glycoantigen tumor marker, because it is widely present in the pancreas, gallbladder, liver, stomach, colorectum, bladder and uterus, and its tumor recognition spectrum is wider than CA19-9, so it is also a universal tumor marker-related antigen, rather than a tumor marker specific to an organ. CA50 can be detected in various malignant tumors with different positive rates. The positive detection rate for pancreatic cancer and gallbladder cancer is the first, accounting for 94.4%; the others are liver cancer (88%), ovarian and uterine cancer (88%) and malignant pleural fluid (80%) in order. 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, stomach cancer, colorectal cancer and ovarian cancer. CA242 is a glycolipid antigen related to pancreatic cancer, gastric cancer and colorectal cancer. Serum CA242 has good sensitivity (80%) and specificity (90%) for the diagnosis of pancreatic cancer and colorectal cancer. The serum CA242 level of patients with lung cancer, liver cancer and ovarian cancer can be increased. CA72-4 is one of the best tumor markers for the diagnosis of gastric cancer, with high specificity and sensitivity up to 28-80%, if combined with CA19-9 and CEA, it can monitor more than 70% of gastric cancer. 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 extremely 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, and ovarian cancer also have a certain positive rate. 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. Detection of ferritin has diagnostic value for metastatic tumors of the liver. 76% of patients with liver metastases have ferritin levels higher than 400 μg/L. When liver cancer is present, the low value of AFP measurement can be supplemented by ferritin measurement to improve the diagnostic rate. Ferritin is also elevated in cases of 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 the seminal plasma. PSA is mainly found in prostate tissue and does not exist in women. The level of PSA in normal male serum is very low, with a serum reference value of <4 μg/L; PSA is organ-specific, but not tumor-specific. The positive rate for the diagnosis of prostate cancer is 80%. Benign prostate disease is also seen with varying degrees of elevated serum PSA levels. Serum PSA measurement is a monitoring indicator for postoperative recurrence and metastasis of prostate cancer and for the observation of efficacy. It is present in the blood in two forms: bound PSA and free PSAF-PSA/T-PSA ratio is an effective indicator to differentiate prostate cancer from 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. 11.Prostate acid phosphatase (PAP) elevated serum PAP of prostate cancer is an important indicator of prostate cancer diagnosis, staging, efficacy observation and prognosis. Prostatitis and prostate enlargement PAP 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 based on this level. Serum β2-MG can be increased in renal failure, inflammation and various diseases. Therefore, increased 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, which 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. The serum NSE concentration can be significantly increased in neuroblastoma and neuroendocrine cell tumor. Cytokeratin 19 (Cyfra21-1) Cyfra21-1 is a soluble fragment of cytokeratin-19. Cyfra21-1 is the preferred marker for non-small cell lung cancer, especially squamous lung cancer. Cyfra21-1 is also a good marker for breast cancer, bladder cancer and ovarian cancer, and is a good adjuvant for diagnosis and treatment monitoring. 15.Squamous cell carcinoma antigen (SCCA) is a tumor-associated antigen TA-4 extracted from cervical squamous epithelial cell carcinoma tissue, with a minimal serum content of <2.5 μg/L. SCCA is a tumor marker for squamous carcinoma, and is suitable for the auxiliary diagnosis, treatment observation and recurrence monitoring of cervical, lung squamous, esophageal, head and neck, and bladder cancer. 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. With 10kU/mL as the threshold value, the sensitivity for the diagnosis of bladder cancer is 70% and the specificity is 78.5%. The sensitivity for the diagnosis of invasive bladder cancer was 100%. 17.α-L-amyloidase (AFU) AFU is another sensitive and specific new marker for the detection of primary hepatocellular liver cancer. The serum AFU activity of primary hepatocellular carcinoma patients is significantly higher than that of 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 liver cancer, lung cancer, breast cancer, ovarian or uterine cancer, and even in some non-neoplastic diseases such as cirrhosis, chronic hepatitis and gastrointestinal bleeding, which are also mildly elevated. The use of AFU should be measured simultaneously with AFP, which can improve the diagnosis rate of primary liver cancer and has a better complementary effect. Joint testing of tumor markers: The clinical significance of single elevation of tumor markers is not significant, only the dynamic and continuous elevation is meaningful. If a certain tumor marker or several tumor markers are found to be continuously elevated during physical examination, then one should be more alert, but there is no need to be overly worried, further examination by CT, ultrasound, MR or the most advanced PET/CT is needed, and if necessary, pathological examination is required to make a clear diagnosis. The purpose of the combined test is to complementarily increase the positive rate. In order to improve the accuracy and detection rate of tumor markers in clinical diagnosis, it is recommended to adopt the method of combined testing for some tumors. Application of tumor marker test: The application of tumor marker test is significant and is summarized as follows: 1. application of tumor census and screening program; 2. tumor diagnosis and differential diagnosis; 3. judgment of efficacy and prognosis; 4. determination of biological characteristics and disease stage; 5. monitoring of surgery, chemotherapy and radiotherapy; 6. determination of primary tumor of metastatic tumor of unknown origin; 7. multiple tumor The combined application of multiple tumor markers to improve detection efficiency.