Abstract
Background: Several studies have indicated an association between tumor necrosis factor-alpha (TNF-α) or interleukin(IL)-6 gene polymorphisms and the risk of lung cancer. However, the conclusions remain controversial. The aim of this study is to examine the association of tumour necrosis factor-alpha (TNF-α) and interleukin-6（IL-6） gene polymorphisms with the risk of developing lung cancer. Methods: We searched several electronic databases, including PubMed and Excerpt Medica Database (EMBASE). The effects of three polymorphisms, TNF-α-308G/A, IL-6-174G/C and IL-6-634C/G, were evaluated. The pooled odds ratio (OR) with 95% confidence interval (CI) was calculated by RevMan software. Heterogeneity was also assessed. Results: For a total of 17 studies involving 4,094 cases and 4,988 controls, were identified in this meta-analysis. Based on our results, we found an association between the TNF-α-308G/A polymorphism and lung cancer risk under the dominant model (GG+GA vs. AA, OR = 0.60, 95% CI: 0.40 to 0.89). For the IL-6-174G/C polymorphisms, the pooled ORs (95% CI) of GG/GC vs. CC, GG vs. GC/CC, GC vs. CC, and GG vs. CC were 1.22 (1.02 to 1.46), 1.22 (1.01 to 1.48), 1.22 (1.01 to 1.48), and 1.12 (0.87 to 1.44), respectively. For the IL-6-634C/G polymorphisms, the pooled ORs (95% CI) of CC/CG vs. GG, CC vs. CG/GG, and C vs. G were 1.04 (0.68 to 1.58), 0.69 (0.57 to 0.85), and 0.79 (0.67 to 0.93) respectively. Conclusions: The results of our analysis of these IL-6 polymorphisms revealed an association between IL-6 and lung cancer risk. This association, however, was not as strong as the association between TNF-α-308G/A polymorphisms and lung cancer risk. Because the current study was limited in sample size, further studies are needed to reveal more precise associations.
Association of Genetic Polymorphisms in Tumour Necrosis Factor-alpha (TNF-α-308G/A) and Interleukin-6 (IL-6-174G/C and IL-6-634C/G) with lung cancer risk: a meta-analysis
