Helicobacter pylori genotypes determine risk of non-cardia gastric cancer and intestinal- or diffuse-type GC in Ardabil: A very high-risk area in Northwestern Iran.

Frequency of the Helicobacter pylori vacA gene polymorphism and its association with gastric cancer (GC) was assessed in Ardabil, a very high-risk area in Northwestern Iran. We determined the presence of the H. pylori 16S rDNA gene and the vacA s-, m-, i-, and d-region genotypes in DNA from fresh gastric biopsies. Patients with GC were classified based on both the anatomic site and the histopathologic type of tumor Of 135 patients, including 57 with non-atrophic gastritis (NAG) and 78 with GC, 103 were infected by H. pylori. The vacA i1 and d1 genotypes were significantly linked to an increased risk of GC, where both cardia (CGC) and non-cardia GC (NCGC) patients were entered into the analysis. The adjusted OR was 9.59 for i1 and 4.39 for d1. Furthermore, i1 was significantly linked to an increased risk of the intestinal-type adenocarcinoma (OR = 14.04) and d1 to the risk of the diffuse-type adenocarcinoma (OR = 7.71). The presence of the m1-type of vacA in combination with i1 or d1 further increased the risk of GC. When the analysis was restricted to NCGC, the adjusted OR for i1 and d1, was 37.52 and 7.17, respectively. No significant association was found between genotypes and the risk of GC in the cardia site of the stomach. It is proposed that the new types of H. pylori vacA, i1 and d1, might be important determinants of NCGC risk in Ardabil. The m1, not independently, but in combination might further define the risk of GC. i1and d1 might also predict the risk of the intestinal- and diffuse-type adenocarcinomas, respectively.