Abstract
BackgroundSeveral studies have indicated an association between tumor necrosis factor-alpha (TNF-α) or interleukin (IL)-6 gene polymorphisms and lung cancer risk. However, the conclusions remain controversial.MethodsAn English literature screening about case-control trials with regard to TNF-α (-308G/A) or IL-6 (174G/C) polymorphisms and lung cancer susceptibility was performed on PubMed, EMBASE, and EBSCO until November 2012. The pooled odds ratio (OR) and 95% confidence intervals (CI) were calculated using STATA 11.0. Sensitivity analysis was performed by sequential omission of individual studies. Publication bias was evaluated by Egger’s linear regression test and funnel plots.ResultsEight eligible studies, including 1,690 patients and 1,974 controls, were identified in this meta-analysis. Compared with the control, no significant association was revealed between TNF-α-308G/A (GG + GC vs. CC: OR = 1.10, 95% CI: 0.73 to 1.64; GG vs. GC + CC: OR = 1.02, 95% CI: 0.81 to 1.27; GC vs. CC: OR = 1.13, 95% CI: 0.73 to 1.77; GG vs. CC: OR = 1.04, 95% CI: 0.80 to 1.36; G vs. C: OR = 1.03, 95% CI: 0.90 to 1.18) or IL-6 174G/C (GG + GC vs. CC: OR = 1.10, 95% CI: 0.73 to 1.64; GG vs. GC + CC: OR = 1.02, 95% CI: 0.81 to 1.27; GC vs. CC: OR = 1.13, 95% CI: 0.73 to 1.77; GG vs. CC: OR = 1.04, 95% CI: 0.80 to 1.36; G vs. C: OR = 1.03, 95% CI: 0.90 to 1.18) and lung cancer risk. The pooled OR remained unchanged after removing the maximum-weight study and no publication bias was observed.ConclusionsThe study raises the possibility of no correlation between the polymorphisms of the two genes and lung cancer susceptibility. However, further researches with large-sample or subgroup analyses are necessary to validate the conclusions.
Highlights
Several studies have indicated an association between tumor necrosis factor-alpha (TNF-α) or interleukin (IL)-6 gene polymorphisms and lung cancer risk
The study raises the possibility of no correlation between the polymorphisms of the two genes and lung cancer susceptibility
Literature screening Eligible studies were identified by searching electronic databases including PubMed, Excerpt Medica Database (EMBASE, http://www.elsevier.com/online-tools/embase), and EBSCOhost Online Research Databases (EBSCO, http:// www.ebscohost.com/) for relevant reports published before November 2012 using the following terms: (TNF odds ratio (OR) tumor necrosis factor OR IL-6 OR interleukin 6) AND (Lung Cancer OR lung carcinoma OR lung tumor) AND
Summary
Several studies have indicated an association between tumor necrosis factor-alpha (TNF-α) or interleukin (IL)-6 gene polymorphisms and lung cancer risk. Lung cancer is one of the most common causes of cancer-related mortality worldwide, being responsible for approximately 87,750 deaths in men and 72,590 in women in 2012 [1]. Cytokines from inflammatory cells can increase intracellular reactive oxygen and nitrogen species and cause DNA damage and epigenetic changes (that is, promoter hyper-methylation), eventually silencing tumor suppressors and promoting tumor initiation [4]. Regulation of pro-inflammatory cytokine expressions can inhibit tumor cell proliferation, angiogenesis, invasion, and meta-stasis, but stimulate cells apoptosis [5,6]. Tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6 are pleiotropic cytokines involved in inflammatory response and cancer pathogenesis. Previous studies have indicated that the high levels of both cytokines are
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call