AB123. IL-6 2174G>C polymorphism and cancer risk: a meta-analysis involving 29,377 cases and 37,739 controls

Abstract: Interleukin-6 (IL-6) is a multifunctional cytokine involved in different physiologic and pathophysiologic processes and plays important roles in the etiology of cancer. The -174G[C polymorphism of the IL-6 gene influencesIL-6 transcription and has been implicated in cancer risk. However, published data have been conflicting. To derive a more precise estimation of the relationship, a meta-analysis of 29,377 cancer cases and 37,739 controls from 50 published cases—control studies was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between -174G> C polymorphism and cancer risk. Overall meta-analysis indicated that no association was found between -174G>C genotypes and cancer risk. However, the positive association was found in bladder cancer (OR =4.33, 95% CI: 1.93-9.71 for CC vs. GC, OR =2.81, 95% CI: 1.39-5.68 for CC vs. GG, and OR =2.19, 95% CI: 1.32-3.64 for CC vs. GG/GC), and among Asians (OR =2.08, 95% CI: 1.07-4.06 for CC vs. GG, and OR =2.20, 95% CI: 1.02-4.74 for CC vs. GG/GC) and Africans (OR =1.61, 95% CI: 1.07-2.42 for GC vs. GG). This meta-analysis showed the evidence that the -174G>C of the IL-6 gene was a low-penetrance susceptibility gene for bladder cancer. Further larger, preferably prospective studies are needed to confirm this relationship.

Keywords: IL-6; polymorphism; cancer risk; meta-analysis; molecular epidemiology