Role of cytokine gene polymorphisms in gastric cancer risk in Chile

To assess the role of pro- and anti-inflammatory polymorphisms in gastric cancer susceptibility. We genotyped 12 polymorphisms in eight cytokine genes (Interleukin-1β -IL1B-, IL8, IL17A, IL17F, IL32, tumor necrosis factor-α -TNF-, IL1RN, IL10) in a case-control study of 147 patients with gastric cancer and 172 controls. Single polymorphism analysis revealed an association between the IL10 -592C>A single nucleotide polymorphism and cases with moderately- or well-differentiated tumors [AA vs. GG, odds ratio (OR)=3.01; 95% confidence interval (CI)=1.08-8.50]. We further analyzed gene-gene interactions using a combined attribute network implemented in multifactor dimensionality reduction software. The analysis revealed an interaction between IL8 -251A>T and IL32 rs28372698 SNPs among cases with moderately- or well-differentiated tumors. Homozygosity for both IL8 -251T and IL32 T alleles increases the odds for developing gastric cancer up to 2.63-fold (OR=2.63; 95% CI=1.15-6.03). This association was higher compared to the homozygosity for the IL8-251 T allele alone (OR=1.11; 95% CI=0.51-2.43) or the IL32 T allele alone (OR=1.21; 95% CI=0.54-2.72). These findings suggest that IL10 -592C>A increases the odds for developing gastric cancer. An interaction between IL8 -251A>T and IL32 rs28372698 SNPs is also proposed.