S100A8 and infection: Strains isolated in East Asian countries such as Japan, China, and Korea, however, are almost all cagA-positive strains.46cagA-positive H. pylori strains are associated with acute gastritis, peptic ulceration, and gastric cancer.40,47 It was first reported in 1995 that infection with cagA-positive strains increased the risk of gastric cancer, with a risk that was at least one order of magnitude higher risk than that of cagA-negative strains.48