The five lung cancer tumor markers can be used to assist in the diagnosis of early lung cancer, timely detection of recurrence, as well as to observe the effect of the disease treatment process and guide the use of drugs, etc. Lung cancer tumor markers mainly include carcinoembryonic antigen, cytokeratin 19, neuron-specific enolase, glycan antigen 19-9, and squamous cell carcinoma antigen, and if the above indicators are found to be abnormal, the diagnosis can be clarified through biopsy. In the screening stage of lung cancer, if the five tumor markers are found to be increased, it helps to detect the tumor at an early stage. After treatment, if tumor marker five decreases, it usually indicates that the treatment is effective, and if tumor marker five increases again, it may indicate tumor recurrence. Therefore, Tumor Marker V can be used to indicate whether the current treatment is effective or not, and the treatment can be adjusted according to the tumor markers, thus ensuring the effectiveness of treatment. The five tumor markers for lung cancer can be used not only for lung cancer, among which carcinoembryonic antigen can also be used for the early diagnosis of colon cancer, rectal cancer, breast cancer and other malignant tumors, while glycoantigen 19-9 can also be used for the diagnosis of pancreatic cancer, colorectal cancer and rectal cancer, and squamous cell carcinoma antigen can be seen in cervical cancer, nasopharyngeal cancer and esophageal cancer. In addition cytokeratin 19 is more sensitive for squamous epithelial cell carcinoma, and neuron-specific enolase is more sensitive for small cell lung cancer.