Association of genetic variations in IL-6/IL-6R pathway genes with gastric cancer risk in a Chinese population

Interleukin-6 (IL-6) and its receptor (IL-6R) were regarded to be responsible for the occurrence of gastric cancer for their regulation roles in the inflammation. The genetic variations in these two genes (IL-6: rs6949149, rs1800796, rs10499563 and IL-6R: rs2228145) have been suggested to be associated with gastric cancer risk. However, the published results were inconsistent among subjects of different ethnicity. To evaluate such an association in Chinese population, we carried out this case-control study based on 473 patients with gastric cancer and 474 healthy controls, whose genotypes were detected by the Sequenom MassARRAY platform, and Helicobacter pylori infection was assessed by immunogold testing kit. This study showed that rs1800796 CG genotype was associated with decreased risk of gastric cancer (adjusted OR = 0.75, 95% CI: 0.57-0.99, p = 0.043). The stratified analysis revealed that, in the Helicobacter pylori negative infection subgroup, rs2228145 AC (adjusted OR = 0.64, 95% CI: 0.42-0.97) and AC/CC (adjusted OR = 0.66, 95% CI: 0.45-0.99) genotypes were associated with decreased risk of gastric cancer, respectively. In contrast, in the Helicobacter pylori positive infection subgroup, rs10499563 TC (adjusted OR = 0.64, 95% CI: 0.43-0.95), CC (adjusted OR = 0.35, 95% CI: 0.14-0.90), TC/CC (adjusted OR = 0.59, 95% CI: 0.40-0.87) genotype were associated with decreased gastric cancer risk, respectively. Moreover, in the male subgroup, rs1800796 CG (adjusted OR = 0.61, 95% CI: 0.44-0.84) and CG/GG (adjusted OR = 0.67, 95% CI: 0.49-0.91) genotype were associated with decreased risk of gastric cancer, respectively. In short, this study suggested that IL-6R rs2228145 and IL-6 rs10499563 genotype were associated with decreased risk of gastric cancer for the individuals with negative and positive Helicobacter pylori infection.