Association between interleukin-1 gene polymorphisms and Helicobacter pylori infection in gastric carcinogenesis in a Chinese population

Background and Aim: Helicobacter pylori is a major cause of chronic gastritis and peptic ulcer disease and a definite carcinogen for gastric adenocarcinoma. However, the underlying pathogenic mechanisms are not fully understood. Interleukin-1 (IL-1) is a key cytokine involved in H. pylori-induced gastric inflammation. The present study aimed to determine polymorphisms of IL-1B and IL-1 receptor antagonist (IL-1RN) genes and their association with H. pylori infection and gastroduodenal diseases in Chinese patients. Methods: Three hundred and ninety-nine patients with gastroduodenal diseases (129 chronic gastritis, 127 duodenal ulcer and 143 non-cardiac gastric cancer) and 264 healthy controls were genotyped for IL-1B-511 and IL-1RN gene polymorphisms by the PCR-RFLP method. H. pylori infection status was determined by a validated serological test. Results: The frequency of IL-1B-511 T allele was significantly higher in H. pylori positive patients with non-cardiac gastric cancer than in both H. pylori negative patients with non-cardiac gastric cancer (60% vs 46%, P = 0.0342, OR = 1.666, 95% confidence interval [CI]: 1.045-2.656) and in healthy controls (60% vs 48%, P = 0.0071, OR = 1.665, 95%CI: 1.149-2.412). However, the polymorphism was not associated with chronic gastritis and duodenal ulcer. Multivariate logistic regression analyses identified that IL-1B-511 T/T carrier status was an independent risk factor for non-cardiac gastric cancer in the presence of H. pylori infection (adjusted OR = 3.01, 95%CI: 1.27-7.11, P = 0.01), and the frequency of IL-1B-511 T allele was an increased risk factor for developing gastric cancer (P = 0.03, adjusted OR = 2.29, 95%CI: 1.08-4.86). There was no association between IL-1RN gene polymorphisms and H. pylori infection and other gastroduodenal diseases. Conclusion: IL-1B-511 T allele is associated with H. pylori infection in non-cardiac gastric cancer in a Chinese population. The IL-1B-511 gene polymorphism appears to play an important role in gastric carcinogenesis in Chinese patients with H. pylori infection.