Association of the interleukin-1β genetic polymorphism and gastric cancer risk in Japanese

Background. Helicobacter pylori infection is associated not only with gastroduodenal ulcers but with the development of gastric cancer. Interleukin-1 beta (IL-1 beta) is a potent inhibitor of gastric secretion. The -31 C-to-T base transition in the intron of this gene has been reported to be involved in carcinogenic changes within the stomach, especially in H. pylori-infected individuals. Methods. In this study, the -511 T-to-C polymorphism in the IL-1 gene was investigated in 669 patients with gastric diseases. Results. The allelic frequencies of the C allele, which indicates low acid secretion and is a component of a supposedly high-risk genotype for gastric cancer, were 0.48 in H. pylori-negative noncancer controls, 0.52 in H. pylori-positive noncancer controls, 0.57 in subjects with chronic active gastritis (CAG) with H. pylori, 0.58 in subjects with intestinal metaplasia (IM) or CAG without H. pylori, and 0.52 in gastric cancer patients. Significant differences among the groups were observed between the IM or CAG without H. pylori group and the gastric cancer group and between the IM or CAG without H. pylori group and the H. pylori-negative noncancer control group (P < 0.05). Conclusions. The IL-1 beta -511 genetic polymorphism was not associated with gastric cancer in a multistep carcinogenesis model. However, in view of the results for the IM or CAG without H. pylori group, the presence of the C allele may also indicate a risk of mucosal atrophy of the stomach in the Japanese population.