Abstract: ［Abstract］〓Objective〖HTSS〗〓To evaluate the value of progastrinreleasing peptide(ProGRP), Squamous cell carcinoma antigen(SCCAg), Cytokeratin 19 fragment antigen(Cyfra211) and carcinoembryonic antigen（CEA） of 4 tumor markers in combined diagnosis of lung cancer.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓 The 71 cases of lung cancer, 106 cases of benign lung diseases and 214 cases of healthy subjects were randomly selected. The median blood samples from the elbow of 3 groups were collected and the levels of 4 tumor markers were detected by enzymelinked immunosorbent assay. The level of 4 tumor markers, the positive rate and the number of positive indicators in the 3 groups were compared. The diagnostic efficiency(sensitivity, specificity, accuracy, positive predictive value and negative predictive value) of 4 tumor markers alone and combined in the diagnosis of lung cancer were compared.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓The levels of serum ProGRP, SCCAg, Cyfra211 and CEA, positive rate and positive index in lung cancer group were significantly higher than those in healthy control group and benign disease group(P＜005). The ROC curve showed that when 4 tumor markers were diagnosed separately for lung cancer, AUC of ProGRP was the largest(AUC=0.898), CEA(AUC=0.873) and Cyfra211(AUC=0.813) were less, and SCCAg(AUC=0.798) were the lowest. The AUC of the 4 markers was increased significantly after combined diagnosis(AUC=0.975). The best cutoff point Youden index is derived ProGRP>47.5 ng/L, SCCAg>2.12 g/L, Cyfra211>3.41 g/L and CEA>5.98 g/L. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of 4 tumor markers combined diagnosis were significantly higher than those of separate diagnosis. 
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓The combined diagnosis of lung cancer with ProGRP, SCCAg, Cyfra211 and CEA has high diagnostic efficiency.

Key words: lung neoplasms, tumor markers, biological, diagnosis