The five indicators of lung cancer specifically refer to carcinoembryonic antigen, neuron-specific enolase, squamous epithelial cell carcinoma antigen, cytokeratin 19 fragment, and glycoconjugate antigen 125, and the normal values of these five indicators are as follows: 1. Carcinoembryonic antigen. Carcinoembryonic antigen, or CEA, has a normal value of less than 5 µg/L. 2. Neuron-specific enolase. Neuron-specific enolase, or NSE, has a normal value of less than 12.5 U/mL. 3. squamous epithelial cell carcinoma antigen. Squamous epithelial cell carcinoma antigen, or SCC, has a normal value of less than 5 μg/L. 4. Cytokeratin 19 fragment. Cytokeratin 19 fragment, CYFRA21-1, with a normal value of less than 3.3 μg/L. 5. Glycoantigen 125: Glycoantigen 125 is CA125, and the normal value is less than 35 U/mL. The five indicators of lung cancer can provide reference significance in the stage of tumor screening, and abnormal again after tumor treatment also suggests the possibility of recurrence, and also has guidance significance on the use of drugs in the process of tumor treatment. Mild elevation of a single index is of little clinical significance. If several indexes are significantly elevated at the same time, it is recommended to combine with imaging and pathology to further determine whether lung cancer is present.