Considering the above, this study aimed at analysis of gene expression manifested by cagPAI (including cagA and virB/D complex: virB4, virB7, virB8, virB9, virB10, virB11, virD4) and by vacA in Helicobacter pylori strains isolated from patients with non-atrophic gastritis, atrophic gastritis or gastric cancer. This evidence concerns the gene S100A8 and chronic atrophic gastritis.