The following five tumor markers are monitored for lung tumors: carcinoembryonic antigen (CEA), glycoconjugate antigen 125 (CA125), cytokeratin 19 (CYFRA21-1), neurospecific enolase (NSE), and squamous epithelial cell carcinoma antigen (SCC), of which CEA with CA125 aids in the diagnosis of lung adenocarcinoma, CEA with SCC or CEA with CEA and CA125, CEA and SCC or CEA and CYFRA21-1, mainly assist in the diagnosis of squamous lung cancer, and CEA and NSE assist in the diagnosis of small cell lung cancer. These tumor markers are only used to assist in the diagnosis of tumors, but not for the final diagnosis of tumors. They also have some auxiliary value in evaluating the efficacy of treatment and monitoring changes in the condition of tumor patients.