On the other hand, after considering many antigen targets for detection, we found that, among the many virulent factors associated with H. pylori bacterium, such as CagA, VacA (Vacuolating cytotoxin), and BabA (blood group antigen binding adhesin), the CagA virulent factor is very important for H. pylori diagnosis since it has been reported that CagA-positive patients may be related to more severe gastritis [36], and that they may even indicate a greater tendency towards the development of cancer [37] than CagA-negative patients. Here, S100A8 is linked to gastritis.