Influence of survivin and Bcl-2 expression on the biological behavior of non-small cell lung cancer

Survivin and Bcl-2 are generally considered to be inhibitors of apoptosis and are frequently overexpressed in several types of human cancers. However, their role in regulating the biological behavior of non-small cell lung carcinoma (NSCLC) remains controversial. We aimed to determine the expression of survivin and Bcl-2 and explore their correlation with clinicopathological features and prognosis. The expression of survivin and Bcl-2 proteins in 62 specimens of NSCLC tissues and 30 specimens of tumor adjacent tissues was detected using immunohistochemistry. The correlation between protein expression and clinicopathological features and prognosis was analyzed. The percentage of survivin-positive samples obtained from NSCLC tissues was 58.06% (36/62), which was significantly higher compared to that in normal lung tissues (10%, 3/30; P<0.05). Similarly, the percentage of Bcl-2-positive samples obtained from NSCLC tissues was statistically higher compared to that from normal lung tissues (51.61%, 32/62 vs. 6.67%, 2/30; P<0.05). Survivin expression was closely correlated with tumor differentiation, lymph node metastasis and TNM stage (P<0.05), while Bcl-2 expression was only associated with TNM stage (P<0.05). The expression of survivin was positively correlated with that of Bcl-2 (P<0.05). A five-year follow-up study revealed that the expression of survivin and Bcl-2 was negatively correlated with post-operative survival duration. Our findings suggest that survivin and Bcl-2 may act synergistically in the occurrence, development, invasion and metastasis of NSCLC, both of which are up-regulated in NSCLC tissues. The co-expression of survivin and Bcl-2, which is closely related to malignancy, may serve as a biomarker for predicting prognosis.