Risks of interleukin‐1 genetic polymorphisms and <scp>Helicobacter pylori</scp> infection in the development of gastric cancer

<jats:title>Summary</jats:title><jats:p><jats:bold>Background</jats:bold> : The host genetic factors that determine the clinical outcomes of <jats:italic>Helicobacter pylori</jats:italic>‐infected individuals remain unclear.</jats:p><jats:p><jats:bold>Aim</jats:bold> : To elucidate the risks of host interleukin‐1 (IL‐1) genetic polymorphisms and <jats:italic>H. pylori</jats:italic> infection in the development of gastric cancer.</jats:p><jats:p><jats:bold>Methods</jats:bold> : In a case–control study of 164 controls and 142 patients with gastric cancer, the IL‐1B‐511 biallelic polymorphisms and the IL‐1RN penta‐allelic variable number of tandem repeats were genotyped.</jats:p><jats:p><jats:bold>Results</jats:bold> : The carriage of IL‐1RN*2, male gender, old age and <jats:italic>H. pylori</jats:italic> infection independently increased the risk of gastric cancer, with odds ratios of 3.3 [95% confidence interval (CI), 1.4–7.7], 2.1 (95% CI, 1.2–3.8), 5.3 (95% CI, 3.1–9.0) and 2.2 (95% CI, 1.3–3.8), respectively. <jats:italic>H. pylori</jats:italic>‐infected individuals who were carriers of IL‐1RN*2 showed increased risks of both intestinal and diffuse types of gastric cancer, with odds ratios of 11.0 and 8.7, respectively. In addition, these individuals also had a higher score of intestinal metaplasia in the corpus than did uninfected non‐carriers.</jats:p><jats:p><jats:bold>Conclusions</jats:bold> : This study is the first to verify IL‐1RN*2 as an independent factor governing the development of gastric cancer in Asian individuals. A combination of <jats:italic>H. pylori</jats:italic> testing and host genotyping may target the eradication of <jats:italic>H. pylori</jats:italic> to high‐risk individuals.</jats:p>