In H. pylori-associated atrophic gastritis, gastric epithelial cells undergo phosphorylation, which is accompanied by tyrosine protein activity.[54] Tyrosine protein phosphorylation activates extracellular signal-regulated kinase 1/2 (ERK1/2).[55] ERK1/2 affects atherosclerotic progression and reduces atherosclerotic plaque stability.[56] The role of protein tyrosine kinase is broad and its role in these 2 conditions deserves further investigation. The gene discussed is PROS1; the disease is chronic atrophic gastritis.