S100A8 and gastric cancer: Interestingly, in serum-derived exosomes from four GC patients infected with CagA-positive H. pylori, Shimoda et al. [187] detected the protein CagA, a major H. pylori virulence factor encoded using the cytotoxin-associated gene A. CagA-positive exosomes determined morphological modifications in gastric epithelial cells and GC cells, suggesting a link between functional CagA exosome delivery into cells and the development of extragastric disorders associated with CagA-positive H. pylori infection.