H. pylori contains various pathogenic factors such as cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), neutrophil activating protein (NAP), outer membrane proteins (OpiA, HopQ) (Palframan et al., 2012), which activate various signaling pathways such as ERK/MAPK, PI3K/Akt, NF-κB, Wnt/β-Catenin, JAK-STAT, Hippo, etc. and promote aberrant transcription of downstream pro-inflammatory/anti-inflammatory, carcinogenic/anti-cancer target genes, which is the key mechanism of H. pylori-induced progression of chronic gastritis to GC. This evidence concerns the gene S100A8 and gastric cancer.