Promoter polymorphisms of IL2, IL4, and risk of gastric cancer in a high‐risk Chinese population

Abstract

Interleukin 2 (IL2) is a typical Th1 cytokine, and interleukin 4 (IL4) is an inducible Th2 cytokine. These cytokines are critical mediators of the Th1/Th2 balance and apoptosis potential and involved in the process of inflammation-mediated carcinogenesis in human organs, including the gastrointestinal tract. Therefore, we tested the hypothesis that functional variants in IL2 and IL4 were associated with risk of gastric cancer by genotyping two promoter polymorphisms in IL2 G-330T (rs2069762) and IL4 T-168C (rs2070874) in a case-control study of 1045 patients with incident gastric cancer and 1100 cancer-free controls in a high-risk Han Chinese population. We found that, compared with the IL4 -168TT genotype, heterozygous -168TC and combined -168TC/CC genotypes were associated with a significantly decreased gastric cancer risk [adjusted odds ratio (OR) = 0.81, 95% confidence interval (CI) = 0.67-0.98 for -168TC; OR = 0.83, 95% CI = 0.69-1.00 for -168TC/CC, respectively]. Furthermore, this significant protective effect was more evident for gastric cardia cancer patients (adjusted OR = 0.73, 95% CI = 0.56-0.95 for -168TC/CC vs. -168TT). For IL2 G-330T, subjects carrying GT/TT genotypes also had a significantly reduced risk of gastric cardia cancer (adjusted OR = 0.68, 95% CI = 0.46-0.99), compared with those carrying the GG genotype. Our results indicate that IL4 T-168C and IL2 G-330T promoter polymorphisms may contribute to the etiology of gastric cardia cancer in Chinese populations.