The results of the analysis of these indexes and clinicopathological features showed that the level of CEA in serum of patients with lung adenocarcinoma was higher than that of lung squamous cell carcinoma and also higher than that of lung small cell cancer, which was consistent with a literature report [35], but there were no differences in IL-1β, IL-6 and IL-8 among different pathological types. This evidence concerns the gene CEACAM5 and small cell lung carcinoma.