Molecular epidemiology of genetic susceptibility to gastric cancer: focus on single nucleotide polymorphisms in gastric carcinogenesis.

Gastric cancer is a disease of gene-environment interactions, as suggested by the varying geographic patterns of its incidence. Even in areas with high rates of Helicobacter pylori infection, only a small proportion of infected individuals develop gastric cancer. Genetic susceptibility to gastric cancer can be investigated by common genetic variants, such as single nucleotide polymorphisms (SNPs), in various genes that regulate multiple biological pathways. The susceptibility to gastric carcinogenesis has a substantial influence on the population attributable risk by modulating the effects of environmental risk factors. Despite recent progress in the field of the molecular epidemiology of cancer, a re-evaluation of gastric cancer susceptibility and potentially functional SNPs in candidate genes is necessary, given the inconsistency of previous reported studies. This review focuses on genetic variants that contribute to the etiology of gastric cancer, particularly those SNPs involved in inflammatory response, metabolism of chemical carcinogens, DNA repair, and tumor suppression. In the future, well-designed large multicenter population-based studies will be needed to validate current findings and provide the rationale for identifying at-risk subpopulations for primary prevention of gastric cancer.