Abstract: Objective: To explore the diagnostic value of the combined detection of serum cancer antigen 125(CA125),carbohydrate antigen 242(CA242),carcinoembryonic antigen(CEA),cytokeratin 19 fragments(CYFRA21-1) and neuron specific enolase(NSE),tumor marker,in lung cancer.Methods: The biomarker levels of CA-125,CA242,CEA,CYFRA21-1 and NSE in 80 patients with lung cancer and 46 patients with benign lung disease were measured by the immunoluminometric assay.Results: The levels of CA-125,CA242,CEA,CYFRA21-1 and NSE in the patients with lung cancer were significantly higher than those in the patients with benign lung disease(P<0.01).The high levels of CEA,CA125 and CA242 in the patients with lung adenocarcinoma,squamous carcinoma and small cell lung cancer were found,respectively.The sensitivity of CYFRA21-1 in lung cancer was the highest,followed by CEA,CA125,NSE and CA242.The highest sensitivities of CYFRA21-1 in adenocarcinoma and squamous cell carcinoma were 50.00% and 48.94%,respectively.The sensitivities of CA125 and NSE in small cell lung cancer were the highest(48.15%).The areas under the ROC curve of CA125,CA242,CEA,CYFRA21-1 and NSE were 0.669±0.095,0.608±0.097,0.682±0.096,0.714±0.090 and 0.660±0.096,respectively.The sensitivity and specificity of the combined detection of CA125,CA242+CEA,CYFRA21-1 and NSE in the diagnosis of lung cancer were high and good(70.00% and 84.78%),respectively.The specificities of the CYFRA21-1 and CYFRA21-1 combined with other factors in the diagnosis of adenocarcinoma were the same(50.00%),but the Youden index of the latter was more than the former.The sensitivities of the combined detections of CA125,CA242,CEA and CYFRA21-1 in diagnosing squamous cell carcinoma and CA125,CA242+CEA,CYFRA21-1 and NSE in diagnosing small cell lung cancer were the highest,which were 72.34% and 88.89%,respectively.Conclusions: The single detection of CA125,CA242,CEA,CYFRA21-1 and NSE has certain significance in the diagnosis of lung cancer,but the sensitivity and specificity of which are limited.The combined detection of multi-markers can improve the sensitivity and specificity in diagnosing the lung cancer.