Interleukin polymorphisms andHelicobacter pyloriinfection are believed to play critical roles in DNA methylation, a process frequently associated with carcinogenesis. The aim of this study was to determine the associations between interleukin polymorphisms and methylation status of three genes related to gastric cancer. Furthermore, the influence of theH. pyloristrains was evaluated.Materials & methods:
75 gastric tumor samples had the DNA extracted for interleukin polymorphisms genotyping by PCR-RFLP, promoter methylation by MS-PCR and detection and subtyping ofH. pyloriby PCR.Results:
In the cardia tumors, methylation in theCOX-2promoter was associated withIL1RN*2(p = 0.015), and the associated genotypesIL1B511T+IL1RN*2seem to be important in the methylation of COX-2 (p = 0.013), especially in the presence ofcagA+ (p = 0.026) andvacAs1(p = 0.025)H. pyloristrains. The associated genotypesIL6CC+TNFGG seem to be involved in the unmethylation ofCDKN2A(p = 0.046), along withH. pylori cagA+infection.Conclusion:
DNA methylation in gastric cancer seems to be influenced by the presence of interleukin polymorphisms and by theH. pylori cagA/vacAs1m1strains.