S100A8 and gastric cancer: To emphasize the positive association between H. pylori infection and gastric cancer risk, isolated H. pylori strains were classified as high virulent/type I, intermediate, and reduced virulent/type II strains, depending on the expression of the virulence factor cytotoxin-associated gene (cagA), the corresponding protein (CagA), and the vacuolating cytotoxin (VacA) [142].