1. Alpha-fetoprotein (AFP): AFP is an acidic glycoprotein that exists in the liver and yolk sac at the early stage of fetal development and gradually disappears soon after birth. The content is extremely low in normal human, normal reference value: 0.25ug/L in serum. Clinical significance: ① AFP is significantly elevated in the serum of patients with primary hepatocellular carcinoma, about 65-75% of patients have AFP > 500ug/L. It has a very high diagnostic value for hepatocellular carcinoma after excluding gonadal tumors and pregnancy. (2) Patients with viral hepatitis and cirrhosis have varying degrees of elevated AFP, but their levels are often <500ug/L. (3) Patients with embryonal tumors of the gonads can have elevated AFP in their serum. ④After the third month of pregnancy, serum AFP begins to rise, reaching a peak at 7-8 months, usually below 400ug/L, and returning to normal 3 weeks after delivery. If AFP is abnormally elevated in the serum of pregnant women, the possibility of fetal neural tube defect malformation should be considered. 2, prostate-specific antigen (PSA): PSA is a single-chain glycoprotein encoded by the hKLK3 gene and secreted by prostate epithelial cells with chymotrypsin activity. Under normal conditions, PSA is mainly secreted into the prostatic fluid to hydrolyze semen coagulation proteins I and II and liquefy semen. The PSA content in semen is high, and only trace amounts of PSA can be detected in normal male serum (0-4ng/ml), and its concentration in semen is about 1 million times higher than the concentration in serum (0.5-5.5mg/ml), normal reference value: <40ug/L. Clinical significance: ①After prostate cancer surgery, the PSA concentration can gradually decrease to normal, if the PSA concentration does not decrease after surgery or increases again after decreasing, the PSA concentration should be considered. If the PSA concentration does not decrease after surgery or increases again after the decrease, metastasis or recurrence of tumor should be considered. ②Serum PSA level may also be elevated in prostate hypertrophy, prostatitis, kidney and genitourinary system diseases, but must be combined with other tests for differentiation. ③The positive rate of anterior adenocarcinoma is about 75%. ④PSA, as a specific marker for prostate cancer, has a specificity of 90%?97% for the diagnosis of anterior adenocarcinoma. It is considered as the most valuable tumor marker for prostate cancer and is widely used for screening, diagnosis and post-treatment monitoring of prostate cancer. 3.Cancer embryonic antigen (CEA): CEA is a glycoprotein firstly found in the serum of colon cancer patients and can also be detected in the serum of fetus from 3 to 6 months old, so it is called carcinoembryonic antigen. Normal reference value: serum <5ug/L. Clinical significance: ① Elevated serum CEA is mainly seen in colon cancer, rectal cancer, pancreatic cancer, gastric cancer, liver cancer, lung cancer, breast cancer, etc. Other malignant tumors also have different degrees of positive rate. ②CEA is detected by continuous follow-up. In general, the serum CEA concentration decreases when the disease improves and increases when the disease deteriorates. ③The percentage of positivity was low although it was elevated to varying degrees in intestinal diverticulitis, rectal polyps, colitis, liver cirrhosis, hepatitis and lung disease. ④98% of non-smoking healthy people have serum <5ug/L. About 39% of smokers have CEA >5ug/L. 4.Glycoprotein 19-9 (CA19-9): It is an antigenic substance related to adenocarcinoma. Normal reference value: serum <37 U/ml Clinical significance: 1) serum CA19-9 levels are significantly higher in pancreatic cancer, gallbladder cancer and bile duct cancer, especially in patients with advanced pancreatic cancer, serum CA19-9 concentration can reach 400,000 U/ml, with a positivity rate of 7 singular 9%. 2) gastric cancer has a positivity rate of about 50% and colon cancer has a positivity rate of about 50%. The positive rate is about 50% for gastric cancer, 60% for colon cancer, and 6 singular 6% for liver cancer. (3) CA19-9 is also elevated in acute pancreatitis, cholecystitis, cholestatic cholangitis, cirrhosis, hepatitis, etc. 5. Cancer antigen 125 (CA125): A glycoprotein detected by Bast et al. in 1983 from epithelial ovarian cancer antigen that can be bound by the monoclonal antibody OC125. Normal reference value: serum <35 U/ml. clinical significance: ① The serum CA125 level is significantly increased in ovarian cancer patients, but it decreases quickly in those with effective surgery and chemotherapy. In case of recurrence, CA125 may be elevated before clinical symptoms. ②Other non-ovarian malignant tumors also have a certain positive rate, such as breast cancer 40%, pancreatic cancer 50%, gastric cancer 47%, lung cancer 44%, colorectal cancer 32%, and other gynecological tumors 43%. ③ Non-malignant tumors, such as endometriosis, pelvic inflammatory disease, ovarian cysts, pancreatitis, hepatitis and liver cirrhosis, have different degrees of elevation, but the positive rate is low. The CA125 is found to be elevated in the thoraco-abdominal fluid, and higher concentrations of CA125 can also be detected in the amniotic fluid. ⑤ In the first 3 months of early pregnancy, there is also the possibility of elevated CA125. 6. human chorionic gonadotropin (hCG): in pregnant female mammals, not only their anterior pituitary gland secretes gonadotropin, but also the chorionic membrane of the placenta. The latter is called chorionic gonadotropin (hCG). The substance in the urine of pregnant women is called HCG (human chorionic gonadotropin) and is composed of a glycoprotein with a molecular weight of about 30,000 and an isoelectric point of pH=2.95, consisting of two subunits. It has a luteinizing hormone-like effect. When HCG is given to animals, the ovaries of young mice develop and mature, while rabbits ovulate before mating. Normal reference value: serum male <5mIU/ml, non-pregnant women <7mIU/ml, pregnant women 530-180000mIU/ml in 6-8 weeks of pregnancy; 10000-320000mIU/ml in 9-12 weeks of pregnancy Clinical significance: ①It is a good indicator for diagnosing early pregnancy, monitoring preterm abortion and ectopic pregnancy. ②In the case of early chorionic epithelial cell carcinoma and chylothorax, the blood hCG is significantly higher than the level of early pregnancy. After chemotherapy or curettage treatment, if hCG decreases insignificantly, it indicates poor treatment effect. After treatment, hCG decreases and later seen to increase again, suggesting recurrence. (3) Teratoma, testicular non-seminomatous cell tumor and embryonal tumor can be seen with elevated hCG. 7, β2 microglobulin (β2M): single-chain polypeptide low molecular protein composed of 100 amino acid residues, molecular weight of 11800daldon. electrophoresis in the β2 region, so called β2m. originated in the human mesenchyme, epithelial cells and normal cells of the hematopoietic system and malignant tumor cells can synthesize β2m. experimental studies have shown that lymphocytes and tumor cells can produce large amounts of β2m, physiological Under physiological conditions, β2m is present in low concentrations in various body fluids such as plasma, urine, cerebrospinal fluid, saliva, colostrum and amniotic fluid. The synthesis rate of β2m in normal human is relatively constant, about 0.13mg/h?kg, and the amount of synthesis in a 70kg person is about 220mg in 24 hours. the rate of synthesis in patients with renal insufficiency is similar to that in normal human. The β2m in body fluid exists as a free monomer, and the β2m entering the blood circulation can be freely filtered from the glomerulus, of which 99.9% is taken up by the proximal tubule in the form of cytosolic drinking, and after ingestion is transferred to the lysosome for degradation into amino acids, in fact, β2m does not return to the blood, the urinary excretion of normal people is very little, about 5μg/h normal reference value: serum <24mg/L, urine <160ug/L. Clinical significance: ① Malignant tumors such as liver cancer, lung cancer, gastric cancer, colon cancer, rectal cancer, multiple myeloma, non-Hodgkin's lymphoma, chronic lymphocytic leukemia, etc., all have significantly elevated serum β2M, and urinary β2M can also be increased. It can be used as a monitoring indicator for the development of malignant tumors. ②Renal diseases such as acute and chronic pyelonephritis, tubular inflammation, congenital tubular acidosis, tubular drug damage, tubular heavy metal toxic damage, etc., have elevated urinary β2M. ③In renal transplant rejection, urinary β2M is elevated. ④Immune diseases such as systemic lupus erythematosus, dry syndrome, rheumatoid arthritis, AIDS, etc., β2M in the serum is elevated. 8.Squamous cell carcinoma antigen (SCC) normal reference value: serum <5ug/L. Clinical significance: ①cervical cancer, lung cancer, head and neck cancer, serum SCC is elevated, and its concentration increases with the aggravation of disease stage. ② Hepatitis, cirrhosis, pneumonia, renal failure, tuberculosis and other diseases, SCC is also elevated to some extent 9, glycoconjugate antigen 50 (CA50): glycoconjugate antigen 50 is a kind of glycoconjugate antigen, which mainly exists in malignant tumor tissues such as digestive tract, and the content in normal tissues is extremely low. Normal reference value: serum <24 U/ml. Clinical significance: ①Serum CA50 is increased in pancreatic cancer, colon cancer, rectal cancer and gastric cancer, especially in patients with pancreatic cancer, the increase is most obvious. ②Increased CA50 can also be seen in liver cancer, lung cancer, uterine cancer, ovarian cancer, kidney cancer, breast cancer, etc. CA50 is also elevated in ulcerative colitis, cirrhosis, melanoma, lymphoma, autoimmune diseases, etc. 10.Cancer antigen 15-3 (CA15-3) normal reference value: serum <28 U/ml. clinical significance: ①Patients with breast cancer often have elevated CA15-3, but the sensitivity is low in the early stage of breast cancer, other malignant tumors, such as lung cancer, colon cancer, pancreatic cancer, ovarian cancer cervical cancer, primary liver cancer, etc., also have different degrees of positive rates. (③) Non-malignant neoplastic diseases such as liver, gastrointestinal tract, lung, breast and ovary, the positivity rate is generally less than 10%. 11.Tissue polypeptide antigen (TPA) normal reference value: serum <55 U/L. Clinical significance: ① Elevated serum TPA is mainly seen in bladder cancer, prostate cancer, breast cancer, ovarian cancer and gastrointestinal tract malignancies. It is especially sensitive for the diagnosis of metastatic cell carcinoma of the bladder. Since the level of TPA is related to the proliferation and differentiation of tumor cells, if the level of TPA decreases to normal, it indicates that the tumor treatment is effective. ②Elevated TPA in serum can also be seen in acute hepatitis, pancreatitis, pneumonia and gastrointestinal diseases. (③) Elevated TPA can be seen in the last 3 months of pregnancy. 12. Neuron-specific enolase (NSE): an acidic protease specific to neurons and neuroendocrine cells. Normal reference value: serum <15ug/L. Clinical significance: ①It can be used to identify, diagnose and monitor the therapeutic effect of small cell lung cancer after radiotherapy. The NSE concentration gradually decreases to normal level when the treatment is effective, and increases when the NSE is relapsed. ②It can be used to monitor changes in neuroblastoma, evaluate the efficacy of treatment and predict recurrence. ③Serum NSE can also be increased in neuroendocrine cell tumors, such as pheochromocytoma, islet cell tumor, medullary thyroid carcinoma, melanoma, and retinoblastoma. Although various markers have their own clinical significance, a comprehensive analysis is needed to reach a correct diagnosis. CEA, NSE, TPA, SCC for lung cancer in general; AFP for liver cancer; CEA, CA125, TPA for breast cancer; CEA, CA19-9 for stomach cancer; PSA, PAP (prostate acid phosphatase) for prostate cancer; CEA, CA19-9, CA50 for colorectal cancer. CA199, CEA, CA50 for pancreatic cancer; CA125 for ovarian cancer; AFP, Hcg for testicular tumor; SCC for cervical cancer; TPA for bladder cancer; β2M for myeloma.