S100A8 and peptic ulcer disease: Approximately 30–40% of H. pylori strains isolated in Western countries (e.g., America, Australia) are CagA-negative which are less associated with the occurrence of peptic ulcer and gastric carcinogenesis, whereas almost all H. pylori strains isolated in East Asian countries (i.e., China, Japan, Korea) are CagA-positive with stronger pathogenicity [36].