In recent years, with the continuous development of molecular biology technology, research on tumor markers has been quite active, and has been widely used in the diagnosis and assessment of tumor efficacy, monitoring of recurrence and prognosis in clinic. Carcinoembryonic antigen (CEA): besides elevated CEA in colon cancer, it can also be seen in pancreatic cancer, breast cancer, small cell and non-small cell lung cancer, medullary carcinoma of thyroid and some non-cancerous patients.CEA can be used to assist diagnosis of suspected colorectal cancer patients, with a positive rate of about 50%-60%, but those who are negative can not completely exclude colorectal cancer, and should be examined by other programs. CEA can be positive before surgery and negative after radical surgery, and it is also important reference for postoperative follow-up of colorectal cancer. If CEA is positive, it is suspicious of tumor recurrence and other tests should be done. However, there are a few cases in which CEA is not elevated after tumor recurrence. Neurospecific enolase and cytokeratin 19 fragment: the former is a marker for small cell lung cancer and the latter is a marker for non-small cell lung cancer. Both of them have obvious changes only in middle and advanced lung cancer, so it is often difficult to achieve the purpose of early diagnosis, but they are related to the growth trend of the tumor, which can be combined with clinical judgment of the efficacy of treatment and monitoring of recurrence. CAl9-9: It is elevated in many kinds of adenocarcinomas, such as pancreatic cancer, lung cancer, colon cancer, rectal cancer and gastric cancer. It has high sensitivity in pancreatic, gastric and hepatobiliary cancer, and is a more reliable marker of pancreatic cancer. CAl9-9 may be elevated in patients with acute cholecystitis and cirrhosis of the liver, and it is helpful to determine the prognosis by determining the level of CAl9-9. For example, patients with stage I pancreatic cancer have high value of C19-9 before operation, and it can be reduced to normal range after operation. Measurement of CAl9-9 in the follow-up of patients can predict tumor recurrence before radiographic findings and clinical signs, and can be used in combination with CEA to distinguish between gallstones and gallbladder cancer. In addition, measuring CAl9-9 and CEA in gastric fluid and serum can improve the sensitivity and specificity of screening for gastric cancer. 4, CAl5-3: It exists in many kinds of adenocarcinomas, such as breast cancer, lung adenocarcinoma, ovarian cancer and pancreatic cancer. Early stage of breast cancer, the serum level of CAl5-3 is seldom greater than 30KU/L, while 60%-80% of patients with progressed stage of breast cancer have serum level of CAl5-3 higher than 30KU/L. It can be used to determine the progression and metastasis of breast cancer and to monitor the treatment and recurrence of breast cancer, and it is the marker of high relevance. In terms of sensitivity and specificity of identifying breast cancer, CAl5-3 is better than CEA. CAl25: Normal fetus and adult ovary do not express CAl25 antigen, ovarian epithelial cancer has high sensitivity but low specificity because it is also found in exudate of benign and malignant tumors of the breast, lung, and elevated levels of CAl25 are related to recurrence of the tumor, which is helpful for the follow-up of the disease and as an important reference for the second treatment. Elevated CAl25 level is related to tumor recurrence, which is helpful to follow up the disease as an important reference for the second treatment. 6.Squamous epithelial cell carcinoma antigen: as a marker of squamous carcinoma, with high specificity but low sensitivity, polyclonal antibody was established in 1977, and now it is measured by monoclonal antibody with some improvement, which can be used to monitor the progress of epithelial carcinoma of the cervix, lungs and head and neck. 7. Ferritin: Ferritin is an iron-binding protein, which exists in all kinds of tissues and can be released into the blood under pathological condition, it is not a tumor-specific marker, and there are different degrees of positivity in the blood of patients with many kinds of cancers. The positive rate in liver cancer patients is more than 70%, so it can assist the diagnosis of liver cancer. In addition, protein level is also significantly elevated in patients with progressive breast cancer, which is related to the course of the disease. 8, Carbohydrate antigen 242: CA242 is a salivary acidification of a new type of mucin-like glycan tumor antigen.CA242 has low sensitivity and has no significance in the diagnosis of NSCLC. However, its concentration level is closely related to NSCLL staging and can predict chemotherapy response, which has little significance in suggesting prognosis when compared with staging and physical status. 9, Glutathione S-transferase-π: Some studies have shown that glutathione S-transferase-π plays an important role in NSCLC resistance to alkylating agents, including platinum compounds. 10, P53 protein: P53 protein is a phosphorus-containing protein consisting of 393 amino acids located in the nucleus. Combined detection of tumor markers related to lung cancer: SCLC; combined examination of CEA, NSE; in adenocarcinoma combined detection of CEA, CA125, CA153; in squamous carcinoma combined detection of CEA, SCC, etc. have certain significance in early diagnosis, determination of efficacy, monitoring recurrence, suggesting prognosis. The clinical value of the combined detection of CA50 and CEA in serum for the diagnosis of lung cancer is significantly higher in the lung cancer group than in the tuberculosis group, which is higher than that in the normal group. The combined application of CA50 and CEA in serum can improve the positive rate of lung cancer diagnosis.