Survivin expression in lung cancer: Association with smoking, histological types and pathological stages.

Survivin is expressed in the nucleus and/or cytoplasm of various malignant cells. Nuclear survivin is critical for the completion of mitosis, while cytoplasmic survivin functions as an inhibitor of apoptosis. The expression of survivin has been reported to be associated with the aggressiveness of certain types of cancer. The present study examined the association between cigarette smoking history and the expression of survivin and Ki-67 in lung adenocarcinomas of pathological (p) stages I, II and III. The expression of survivin and Ki-67 in adenocarcinomas was also compared with that of other p-stage I lung cancers, including squamous cell carcinoma (SqCC), large cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SmCCs), of patients with a smoking history. In adenocarcinomas at p-stage I, labeling indices (LIs) of nuclear survivin and Ki-67 were significantly higher in tissue samples from smokers than those from non-smokers; however, the nuclear survivin and Ki-67 LIs in p-stage II and III adenocarcinomas from non-smokers and smokers were similar to those in p-stage I adenocarcinomas of smokers. The nuclear survivin and Ki-67 LIs in adenocarcinomas of smokers at p-stage I were lower than those in SqCCs, LCNECs and SmCCs of smokers at the same stage. Smokers with adenocarcinoma also exhibited a higher survival rate compared with that of smokers with SqCCs, LCNECs and SmCCs. The present results indicated that a history of smoking is associated with increased nuclear survivin and Ki-67 expression in lung adenocarcinomas of p-stage I, but not p-stages II or III. In addition it was revealed that, in smokers, the nuclear survivin and Ki-67 expression in p-stage I adenocarcinomas was lower than that of other p-stage I lung cancer types, and was associated with an enhanced survival rate. In conclusion, smoking is associated with the histogenesis of lung adenocarcinoma but not with the development of lung adenocarcinoma, based on the nuclear expression levels of Ki-67 and survivin.