IL-4/IL-4R and IL-6/IL-6R genetic variations and gastric cancer risk in the Chinese population.

OBJECTIVE: The IL-4/IL-4R and IL-6/IL-6R signaling pathways are involved in immune response and play roles in gastric carcinogenesis. To investigate the association between IL-4/IL-4R and IL-6/IL-6R genetic variations and gastric cancer risk, and their prognostic values, we performed a case-control study. The genotypes of the genetic variations were detected using a Mass-array platform. The Helicobacter pylori infection status was determined using a commercial H. pylori immunogold testing kit. We found that the IL-6 rs1800796 G allele was associated with an increased risk of gastric cancer (GG vs. CC: ORadjusted = 2.20, 95% CI = 1.33-3.63; GG/CG vs. CC: ORadjusted = 1.41, 95% CI = 1.09-1.82). The stratified analysis showed that rs1800796 G allele carriers (GG/CG) were associated with an increased risk of gastric cancer in the following subgroups: age >64 years old (ORadjusted = 1.67, 95% CI = 1.17-2.39), female (ORadjusted = 1.82, 95% CI = 1.09-3.05), positive for H. pylori infection (ORadjusted = 1.54, 95% CI = 1.07-2.22), non-cardiac gastric cancer (ORadjusted = 1.53, 95% CI = 1.15-2.04), stage T3-T4 tumor (ORadjusted = 1.41, 95% CI = 1.06-1.88), and gastric cancer with median to high differentiation (ORadjusted = 1.45, 95% CI = 1.08-1.96). None of the genetic variations were associated with overall survival. In short, we concluded that the IL-6 rs1800796 GG genotype is a risk factor for gastric cancer and that rs1800796 G allele carriers have an increased risk of gastric cancer; this association was stronger in individuals that were >64 years old, female, or positive for H. pylori infection. None of the genetic variations were associated with gastric cancer prognosis.