Abstract: Objective To evaluate the diagnostic value of the serum tumor markers carcinoembryonic antigen (CEA), cytokeratin-19-fragment (CYFRA21-1), squamous cell carcinoma associated antigen (SCCAg), neuron-specificenolase (NSE) and pro-gastrin-releasing peptide (ProGRP) for lung cancers of different pathological types. Methods This study was conducted among patients with established diagnoses of lung adenocarcinoma (LADC, n=137), lung squamous cell carcinoma (LSCC, n=82), small cell lung carcinoma (SCLC, n=59), and benign chest disease (BCD, n=102). The serum tumor markers were detected for all the patients for comparison of the positivity rates and their serum levels. ROC curve was used for analysis of the diagnostic efficacy of these tumor markers either alone or in different combinations. Results In patients with LADC, the positivity rate and serum level of CEA were significantly higher than those in the other groups (P<0.05); the patients with LSCC had the highest positivity rate and serum level of SCCAg among the 4 groups (P<0.05). The positivity rates and serum levels of ProGRP and NSE were significantly higher in SCLC group than in the other groups (P<0.05). CYFRA21-1 showed the highest positivity rate and serum level in LADC group and LSCC group. With the patients with BCD as control, CEA showed a diagnostic sensitivity of 62.8% and a specificity of 93.1% for LADC, and the sensitivity and specificity of SCCAg for diagnosing LSCC were 64.6% and 91.2% , respectively. CYFRA21-1 had the highest diagnostic sensitivity for LADC and LSCC. The diagnostic sensitivity and specificity of ProGRP for SCLC were 83.1% and 98.0%, respectively. When combined, CYFRA21-1 and CEA showed a high sensitivity (78.8% ) and specificity (86.3% ) for diagnosing LADC with an AUC of 0.891; CYFRA21-1 and SCCAg had a high sensitivity (84.1%) and specificity (87.3%) for diagnosing LSCC with an AUC of 0.912. NSE combined with ProGRP was highly sensitive (88.1%) and specific (98.0%) for diagnosis of SCLC, with an AUC of 0.952. For lung cancers of different pathological types, the combination of all the 5 tumor markers showed no significant differences in the diagnostic power from a combined detection with any two of the markers (P>0.05). Conclusion CEA, CYFRA21-1, SCCAg, NSE and ProGRP are all related to the pathological type of lung cancers and can be used in different combinations as useful diagnostic indicators for lung cancers.

Key words: lung cancer; serum tumor markers; pathological type; diagnosis