Thus, the aims of the current study were to determine the expression levels of the TNF-α cytokine gene in tissues samples from gastric cancer patients, chronic gastritis patients and uninfected controls, to evaluate the TNF-α -308 G > A polymorphism, and to determine the influence of H. pylori, cagA, vacA and dupA virulence markers on gastric carcinogenesis. This evidence concerns the gene S100A8 and chronic gastritis.