The H. pylori cag pathogenicity island (cag PAI) is a strain-specific virulence factor that augments cancer risk.5,6 The cag PAI encodes a type IV secretion system (cag T4SS) that facilitates the delivery of peptidoglycan, nucleic acids, lipid metabolites, and the oncoprotein CagA into host cells.7–9 The majority of people infected by H. pylori harboring the cag T4SS do not develop cancer,1,10,11 suggesting that other bacterial constituents affect disease risk. Here, S100A8 is linked to cancer.