1.AFP (alpha-fetoprotein) AFP is the most sensitive and specific indicator for early diagnosis of primary liver cancer and is suitable for large-scale screening. if the blood AFP value of adults is elevated, it indicates the possibility of liver cancer. Significantly elevated AFP level generally indicates primary hepatocellular carcinoma, 70-95% of patients have elevated AFP, the more advanced, the higher the AFP level, but negative does not exclude primary hepatocellular carcinoma. the AFP level to some extent reflects the size of the tumor, its dynamic changes have a certain relationship with the disease, and it is a sensitive indicator showing the treatment effect and prognosis judgment. abnormally high AFP value generally indicates An abnormally high AFP level generally indicates poor prognosis, while an increase in its level indicates deterioration of the disease. Usually, two months after surgical resection of hepatocellular carcinoma, the AFP value should be reduced to less than 20ng/ml. If the value is not reduced much or is reduced but increases again, it indicates incomplete resection or the possibility of recurrence or metastasis. In metastatic hepatocellular carcinoma, the AFP value is usually lower than 350-400ng/ml. AFP is also significantly elevated in germinal gland embryonal carcinoma and ovarian endodermal sinus carcinoma in obstetrics and gynecology. moderately elevated AFP is also common in alcoholic cirrhosis, acute hepatitis and HBsAg carriers. Some cancers of the digestive tract may also show elevated AFP. Elevated AFP in maternal serum or amniotic fluid suggests fetal spina bifida, anencephaly, esophageal atresia, or multiple births. Decreased AFP (in combination with maternal age) suggests that the unborn child is at risk for Down’s syndrome. Normal reference value: 0-15 ng/ml 2. carcinoembryonic antigen (CEA) CEA is difficult to detect in the blood of normal adults. cEA is an important tumor-related antigen. 70-90% of patients with colon adenocarcinoma are highly positive for CEA, and the positive rates in other malignant tumors are in the order of gastric cancer (60-90%), pancreatic cancer (70-80%), small intestine adenocarcinoma (60-83%) , lung cancer (56-80%), liver cancer (62-75%), breast cancer (40-68%), and urological carcinoma (31-46%). The positive rate of CEA in gastric fluid (gastric cancer), saliva (oral cancer, nasopharyngeal cancer) and chest and abdominal fluid (lung cancer, liver cancer) is higher because CEA in these tumor “soaking fluid” may exist before blood. When liver metastasis occurs, the increase of CEA is especially obvious. CEA measurement is mainly used to guide the treatment and follow-up of various tumors, and the continuous observation of CEA concentration in blood or other body fluids of tumor patients can provide an important basis for disease judgment, prognosis and efficacy observation. A large number of clinical practices have confirmed that the preoperative or pre-treatment CEA concentration can clearly predict the status of tumor, survival period and the indication for surgery. The lower the preoperative CEA concentration, the earlier the disease stage, the less the possibility of metastasis and recurrence, and the longer the survival time; on the contrary, the higher the preoperative CEA concentration, the more advanced the disease stage, the more difficult to resect, and the poor prognosis. When surgical resection of malignant tumors is performed, continuous measurement of CEA will help to observe the efficacy. The CEA concentration can also reflect the efficacy of radiotherapy and chemotherapy. As long as the CEA concentration decreases with treatment, it is effective; if the concentration remains the same or even increases with treatment, the treatment plan should be changed. CEA testing can also be used to monitor recurrence and metastasis in patients whose CEA has been normalized by surgery or other treatment methods, with long-term follow-up. The following protocol is usually used: once in the sixth week after surgery; once a month for three years after surgery; once every three months for 3-5 years; once every six months for 5-7 years; and once a year after 7 years. If elevation is found, retest in two weeks; both times are indicative of recurrence and metastasis. Normal reference value: 0-5 ng/ml 3. Cancer antigen 125 (CA125) CA125 is the preferred marker for ovarian cancer and endometrial cancer. if 65U/ml is used as the positive limit, the accuracy rate of stage III-IV carcinoma can reach 100%. CA125 is by far the most important index for early diagnosis, efficacy observation, prognosis judgment, monitoring recurrence and metastasis of ovarian cancer. The combination of CA125 measurement and pelvic examination can improve the specificity of the test. Elevated CA125 levels are a sign of recurrence of female germline tumors. The prognostic evaluation and therapeutic control of ovarian cancer can be facilitated by dynamic observation of serum CA125 concentration, which can decrease significantly after treatment. The serum CA125 in patients with metastatic ovarian cancer is even more significantly higher than the normal reference value. Elevated CA125 can also be seen in ascites caused by various malignant tumors and in many benign gynecological diseases, such as ovarian cysts, endometrial disease, cervicitis and uterine fibroids, gastrointestinal cancer, liver cirrhosis, hepatitis, etc. Normal reference value: 0.1~35 U/ml. 4.Cancer antigen 15-3 (CA15-3) CA15-3 is the most important specific marker for breast cancer. 30%-50% of breast cancer patients have significantly elevated CA15-3, and the change of its level is closely related to the treatment effect, which is the best indicator for breast cancer patients to diagnose and monitor postoperative recurrence and observe the efficacy of treatment. Dynamic measurement is helpful for early detection of recurrence after treatment in stage II and III breast cancer patients; when CA15-3 is greater than 100 U/ml, it can be considered as having metastatic lesions. Serum CA15-3 can also be elevated in patients with lung, gastrointestinal, ovarian and cervical cancers, and should be differentiated, especially to exclude the elevated level caused by some pregnancies. Normal reference value: 0.1-25 U/ml 5. Cancer antigen 19-9 (CA19-9) CA19-9 is a marker related to pancreatic cancer, gastric cancer, colon and rectal cancer, gallbladder cancer, and a large number of studies have proved that CA19-9 concentration is related to the size of these tumors and is the most sensitive marker for pancreatic cancer reported so far. It is the most sensitive marker reported to date for pancreatic cancer. 85%-95% of patients with pancreatic cancer are positive, and CA19-9 measurement helps in the differential diagnosis and disease monitoring of pancreatic cancer. When CA19-9 is less than 1000 U/ml, it has some surgical significance. CA19-9 concentration will decrease after tumor removal, and if it rises again, it can indicate recurrence. There is also a high positive rate for the diagnosis of pancreatic cancer metastasis. When the serum CA19-9 level is higher than 10,000 U/ml, peripheral metastasis almost always exists. The positive rate of gastric cancer, colorectal cancer, gallbladder cancer, bile duct cancer and liver cancer will also be high, and the positive detection rate can be further improved if CEA and AFP are tested simultaneously (for gastric cancer, a combined test of CA72-4 and CEA is recommended). The concentration of CA19-9 can also be increased in benign and inflammatory lesions of the gastrointestinal tract and liver, such as pancreatitis, mild biliary depression and jaundice, but it is often “transient” and the concentration is mostly below 120 U/ml, which must be differentiated. Normal reference value: 0.1~27 U/ml 6.Cancer antigen 72-4 (CA72-4) CA72-4 is one of the best tumor markers for the diagnosis of gastric cancer, with high specificity and sensitivity of 28-80%. CA72-4 level has a significant correlation with the stage of gastric cancer, and generally increases in the stage III-IV of gastric cancer, and the positive rate of CA72-4 in patients with metastasis is much higher than that in non-metastatic patients. In 70% of recurrent cases, CA72-4 concentrations are elevated first. 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. CA72-4 also has different detection rates for other gastrointestinal cancers, breast cancer, lung cancer and ovarian cancer. CA72-4 combined with CA125 as a marker for the diagnosis of primary and recurrent ovarian tumors has a specificity of up to 100%. Normal reference value: 0.1-7 U/ml 7. Cancer antigen 242 (CA242) CA242 is a new tumor-associated antigen whose content increases when tumors occur in the gastrointestinal tract. It has high sensitivity and specificity for pancreatic cancer and colorectal cancer, with positive detection rates of 86% and 62%, respectively, and also for lung cancer and breast cancer. It is used for the differential diagnosis and prognosis of pancreatic cancer and benign hepatobiliary disease, and also for the preoperative prognosis and recurrence identification of colorectal cancer patients. The combination of CEA and CA242 can improve the sensitivity, compared with CEA alone, it can increase 40-70% for colon cancer and 47-62% for rectal cancer. CEA is not correlated with CA242 and has independent diagnostic value, and the two are complementary. Normal reference value: 0-17 U/m 8. Cancer antigen 50 (CA50) CA50 is a marker for pancreatic, colon and rectal 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, and 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%). 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 cancer. It is worth pointing out that CA50 is positive in 80% of AFP-negative hepatocellular carcinoma, and it is also more correct as an indicator of the thoroughness of surgical treatment. In addition, CA50 has a high positive detection rate for malignant pleural fluid, while there are no positive reports for benign pleural fluid, so CA50 testing is also of great value for differentiating benign and malignant pleural fluid. It has also been reported that the concentration of CA50 in gastric juice of patients with atrophic gastritis is significantly altered compared to normal subjects. It is usually considered that atrophic gastritis is a pre-cancerous high-risk stage, so CA50 can be used as one of the pre-cancerous diagnostic indicators. CA50 is also elevated at the onset of pancreatitis, colitis and pneumonia, but decreases with the resolution of inflammation. Normal reference value: 0-20 U/ml 9. Non-small cell lung cancer-associated antigen (CYFRA 21-1) n CYFRA 21-1 is the most valuable serum tumor marker for non-small cell lung cancer, especially for early diagnosis, efficacy observation and prognosis monitoring of patients with squamous cell carcinoma. n CYFRA 21-1 can also be used to monitor the course of transverse muscle-infiltrating bladder cancer, especially for anticipating the recurrence of bladder cancer is of greater value. If the tumor is well treated, CYFRA 21-1 levels will quickly decline or return to normal levels, and changes in CYFRA 21-1 values often precede clinical symptoms and imaging during the progression of the disease. The specificity of CYFRA 21-1 for differentiation from benign lung diseases (pneumonia, tuberculosis, chronic bronchitis, bronchial asthma, emphysema) is relatively good. Normal reference value: 0.10-4 ng/ml 10. Small cell lung cancer-associated antigen (neuron-specific enolase, NSE) NSE is considered the marker of choice for monitoring small cell lung cancer, and is elevated in 60-80% of patients with small cell lung cancer. In remission, 80-96% of patients have normal NSE levels, and if NSE is elevated, it suggests recurrence. Patients with small cell lung cancer show a transient increase in NSE within 24-72 hours after the first round of chemotherapy due to the breakdown of tumor cells. Therefore, NSE is an effective marker for monitoring the efficacy and course of small cell lung cancer and can provide valuable prognostic information. NSE can also be used as a marker for neuroblastoma and has high clinical application for the early diagnosis of this disease. Patients with neuroblastoma also have elevated urinary NSE levels, and serum NSE levels decrease to normal after treatment. The measurement of serum NSE levels is an important reference value for monitoring the efficacy of neuroblastoma and predicting recurrence, and is more meaningful than the measurement of urinary catecholamine metabolites. It is also important for the diagnosis of amine precursor uptake decarboxylation cell tumor, seminoma and other brain tumors. Normal reference value: 0-16 ng/ml 11.Squamous cell carcinoma antigen (SCC) Squamous cell carcinoma antigen (SCC) is a tumor marker with good specificity and was first used for the diagnosis of squamous carcinoma. diagnosis and monitoring, such as: cervical cancer, lung cancer (non-small cell lung cancer), head and neck cancer, esophageal cancer, nasopharyngeal cancer, and squamous cell carcinoma of the vulva. SCC is elevated in the serum of patients with these tumors, and its concentration increases with the stage of the disease. It is used clinically to monitor the efficacy, recurrence, and metastasis of these tumors and to evaluate the prognosis. It has high diagnostic value for cervical cancer: sensitivity for primary squamous cervical cancer is 44%-69%; sensitivity for recurrent cancer is 67%-100% and specificity is 90%-96%; its serological level correlates with tumor development, degree of invasion and whether it is metastatic. SCC concentration decreases significantly after radical cervical cancer surgery; it can indicate recurrence at an early stage, and the increase of SCC concentration in 50% of patients precedes the clinical diagnosis of recurrence by 2-5 months, and it can be applied as an independent risk factor. Adjuvant diagnosis of squamous lung cancer: the positive rate of squamous lung cancer is 46.5%, and its level correlates with the degree of tumor progression; it can improve the sensitivity of diagnosis of lung cancer patients by combining with CA125, CYFRA21-1 and CEA. Prediction of esophageal squamous carcinoma and nasopharyngeal carcinoma: the positivity rate increases with disease progression, and for advanced stage patients, its sensitivity can reach 73%, and the combined detection of CYFRA21-1 and SCC can improve the sensitivity of detection. the positivity rate of stage III head and neck cancer is 40%, and increases to 60% at stage IV. Diagnosis and monitoring of other squamous cancers: head and neck cancer, vulvar cancer, bladder cancer, anal canal cancer, skin cancer, etc. Normal reference value: < 1.5 mg/L 12. Total prostate-specific antigen (TPSA) PSA is a specific marker for prostate cancer and is currently recognized as the only organ-specific tumor marker. Elevated serum TPSA generally indicates the presence of pathology in the prostate (prostatitis, benign hyperplasia or cancer). TPSA is one of the most important indicators for the detection and early detection of prostate cancer, with a positive threshold of greater than 10 μg/L and a diagnostic specificity of 90-97% for prostate cancer. TPSA can also be used for screening and early diagnosis of prostate cancer in high-risk groups and is the first tumor marker recommended by the American Cancer Society for screening men over 50 years of age for prostate cancer. The TPSA assay can also be used to monitor the condition and outcome of patients with prostate cancer or those receiving hormone therapy. 90% of patients with postoperative prostate cancer have serum TPSA values that can be reduced to undetectable trace levels, and if the serum TPSA value is elevated after surgery, it indicates the presence of residual tumor. For those with significant efficacy after radiotherapy, more than 50% of patients have their serum TPSA reduced to normal within 2 months. Normal reference value: 0.01-4.0 ng/ml 13. Free prostate-specific antigen (FPSA) A single serum total PSA (TPSA) assay cannot clearly identify prostate cancer and benign prostatic hyperplasia, mainly because there is crossover between the two groups of patients in the concentration range of 2-20 ng/ml. In contrast, FPSA/TPSA is not affected by this factor and age, and the FPSA/TPSA ratio is used to identify prostate cancer or benign prostatic hyperplasia. The FPSA/TPSA ratio is significantly lower in patients with prostate cancer and higher in patients with benign prostatic hyperplasia. The FPSA test is mainly suitable for untreated patients with TPSA values of 2-20ng/ml. When the TPSA value is lower than 2ng/ml or higher than 20ng/ml, the FPSA/TPSA ratio is not used to distinguish prostate cancer from benign prostatic hyperplasia. Normal reference value: 0.01-2.0 ng/ml FPSA/TPSA: > 0.15 14. α-L-fucosidase (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. It should be measured simultaneously with AFP when using AFU, which can improve the diagnosis rate of primary liver cancer and has a better complementary effect. Normal reference value: 234-414 μmol/L 15. EBV antibody (EBV-VCA) EB virus positivity, family history of nasopharyngeal carcinoma, high incidence of nasopharyngeal carcinoma, and low body immunity may be high-risk factors for developing nasopharyngeal carcinoma. Theoretically, if a person is positive for EBV, it only means that the patient has been previously infected with EBV, but there is no definite conclusion whether it is the direct cause of the development of nasopharyngeal cancer. However, clinical practice and scientific studies have shown that a positive person has a much greater chance of developing nasopharyngeal cancer than a negative person. Nasopharyngeal carcinoma is the most common epithelial tumor with EBV infection, and almost 100% of non-keratinizing nasopharyngeal carcinomas have EBV infection. Therefore, EBV serologic testing can aid in the diagnosis when nasopharyngeal carcinoma is to be differentiated from other cancers of the nasopharynx. In addition, when metastatic cancer is found in the lymph nodes of the neck, a positive EBV serologic test indicates that the primary tumor is likely to be nasopharyngeal cancer. If there is no abnormal finding under nasopharyngeal microscopy, but the EBV serology titer is high or antibody test is positive, then regular observation should be made with prevention, and it is recommended to ask a specialist for further examination for early diagnosis and treatment. The virus-specific antigens formed during EBV infection can be distinguished as early antigen (EA), viral capsid antigen (VCA), nuclear-associated tumor antigen (EBNA), and membrane antigen (MA). Detection of the corresponding antibody responses to these antigens can help in the diagnosis and treatment of EBV-related diseases. VCA antigens are highly immunogenic and VCA-IGM can be detected in the serum of patients initially infected with EBV, after which the IGM antibodies gradually decrease to undetectable levels (normally, IgM antibodies persist for no more than 10 weeks. The titer decreases and sometimes ebbs and flows. A chronic course of any acute infection is rare), almost simultaneously with a gradual increase in VCA-IGG, and can be present throughout life in normal individuals. If this test is negative, EBV infection can be ruled out. EBNA can be divided into six species, of which EBNA1 is the only viral protein expressed in all EBV-associated tumor cells and appears in the nuclei of all persistently infected cells, with relatively late immunogenic expression, forming anti-EBNA-1 antibodies only weeks or months later. An apparently positive test result (second titer stage) indicates a previous infection. A positive VCA test with a titer of 1:160 or higher, combined with a negative or weakly positive anti-EBNA-1 test, indicates an acute, new or recurrent infection. EA are antigens produced early by infected cells and are less immunogenic than VCA, so they induce antibodies that appear later in primary infections, however, in recurrent infections antibodies are usually detected early. Nasopharyngeal cancer stimulates the synthesis of IgA-like EBV antibodies, particularly anti-VCA antibodies. VCA-IgM is usually negative and VCA-IgG titers are increased. The specificity of IGA/VCA for the diagnosis of nasopharyngeal carcinoma has been proven over the years to be lower than that of IGA/EA, but the latter is less sensitive. In addition to IGA, specific non-structural antigens in the early EBV replication cycle – DNA polypeptidase, DNA nuclease, and DNA major binding protein – are also recommended as serological diagnostic indicators. Clinical significance of EBV-VCA antibodies: VCA-IgA ≥ 1:10 is positive, indicating an EBV infection (mostly six months or a long time ago), clinically associated with nasopharyngeal cancer, thymic lymphoepithelial cancer, gastric cancer, rectal cancer, rheumatoid arthritis, non-A non-B hepatitis, erythema scarum, desiccation syndrome, Burkitt’s lymphoma, lymphoma in immunodeficient hosts, and other diseases . VCA-IgM ≥1:5 is positive, indicating a recent infection, (the antibody is elevated in 2-3 weeks after infection, the duration in the body varies) clinically associated with unexplained hair, weakness, infectious mononucleosis, purpura, tamponade, Kawasaki teratology, oral desquamation and other autoimmune diseases; VCA -IgG ≥ 1:80 or more indicates that EBV is activated or activates other viral genes and certain cellular genes, and can be used as a reference tender for EBV or other viral infections. Normal reference value: EBV-VCA antibody Negative 16, tumor-related substances (TSGF) TSGF tumor-related substances combined test (formerly known as malignant tumor-specific growth factor) is a new type of tumor marker that can be used easily and quickly for early adjuvant diagnosis of malignant tumors, and also has high application value for efficacy observation and population screening. Glycolipids, glycoproteins and oligosaccharides, which are composed of glycans, are widely distributed inside and outside cells and in various body fluids, and their metabolic disorders can increase the content in body fluids when cells become cancerous, and are internationally recognized tumor markers. The combination of several small molecule tumor markers together is called TSGF, and because the level of TSGF increases significantly in serum at the early stage of tumor, this characteristic makes it an ideal indicator for early diagnosis of broad-spectrum malignant tumors. TSGF has certain advantages for early cancer detection. The application of TSGF detection and dynamic tracking in population cancer prevention health examination can effectively exclude the interference of false positives and improve the accuracy of detection. It is used to detect early cancer or early recurrent cancer patients without any symptoms, and can be used in population health cancer prevention examination or screening of high-risk groups to detect cancer early and improve the treatment effect through regular testing. TSGF testing is recommended once a year for the natural population, especially those in high cancer-prone areas. As many as dozens of common malignant tumors of different tumor types and organs can be screened by TSGF testing, indicating that TSGF is a broad-spectrum marker of malignant tumors. The TSGF level in the serum of patients with malignant tumors is significantly increased, and the difference between different kinds of malignant tumors is not obvious; while there is no significant difference between benign tumors and healthy people, TSGF is a differentiating indicator of benign and malignant tumors, and can play a role in assisting the diagnosis of malignant tumors. Acute inflammation, collagen disease and other benign diseases will show a transient increase in TSGF value, and after treatment or natural recovery, TSGF value will then decrease, while TSGF recheck value in cancer patients shows continuous positive, and false-positive interference can be excluded by short-term follow-up testing. Clinical case statistics show that 2499 cases of various types of inflammatory diseases have a false positive of 18.7%, and the majority of them can turn negative within a month with the regression of the disease. TSGF is also an indicator of treatment effect and dynamic follow-up of cancer patients. Clinical application data show that TSGF test value of cancer patients before treatment is significantly higher, and after effective treatment, TSGF value in patients’ serum decreases significantly or even drops to normal level; TSGF value increases instead in patients with ineffective treatment or deterioration, recurrence or metastasis. Therefore, TSGF has an important value in the observation of therapeutic efficacy, and the treatment plan can be adjusted according to the TSGF test results in time to achieve the best therapeutic effect Some acute inflammatory diseases (hepatitis, pneumonia, etc.), autoimmune diseases such as systemic lupus erythematosus, rheumatoid diseases, etc. can produce cross-reactivity and cause false positives. Patients with advanced cancer may have TSGF levels below the threshold. Normal reference value: normal human TSGF concentration range is 47±17U/ml; <64U/ml is negative; ≥64U/ml and <71U/ml is suspicious; ≥71U/ml is positive. 17, 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 in metastatic tumors of the liver. 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, it 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. Normal reference value: Male: 30-400 μg/L Female: 13-150 μg/L 18. β2-microglobulin (β2-MG) β2-MG is an adjuvant marker of malignancy and a tumor-associated antigen on some tumor cells. In malignant hematological diseases or other substantial carcinomas, mutant cells synthesize and secrete β2-MG, which can increase the concentration in patients' serum significantly, especially in lymphatic system tumors such as chronic lymphocytic leukemia, lymphocytic sarcoma and multiple myeloma, etc. It is also seen to increase in lung cancer, breast cancer, gastrointestinal tract cancer and cervical cancer. As the serum β2-MG can be significantly higher than the normal value in the early stage of tumor, it can help to distinguish benign and malignant tumors. It has been reported that the ratio of β2-MG in ascites to that in serum is obviously correlated in malignant diseases, and if the ratio of the two is greater than 1.3, it is considered as a manifestation of cancer. Serum β2-MG can not only be elevated in renal failure, various hematologic diseases and inflammation, but also in a variety of diseases, so the increase of serum β2-MG due to certain inflammatory diseases or reduced glomerular filtration function should be excluded. The detection of β2-MG in cerebrospinal fluid is of particular significance for the diagnosis of meningeal leukemia. Normal reference value: 1.58~3.55 μg/ml 19. Pancreatic embryonic antigen (POA) Pancreatic embryonic antigen is another new, sensitive and specific new marker for pancreatic cancer. The positive rate of POA in pancreatic cancer is 95%, and its serum content is greater than 20 U/ml. When malignant tumors such as liver cancer, colorectal cancer and gastric cancer also increase POA, but the positive rate is lower. Normal reference value: 0-7 U/ml 20. gastrin precursor releasing peptide (PROGRP) The gastrin precursor releasing peptide is a new small cell lung cancer marker. PROGRP is a kind of brain and intestinal hormone, a precursor of the small cell lung cancer proliferation factor gastrin releasing peptide. PROGRP as a small cell lung cancer marker has the following characteristics: 1. very high specificity for small cell lung cancer; 2. High positive rate in earlier cases; 3. High reliability of the test due to the large difference in blood concentrations between healthy individuals and patients.