In Helicobacter felis-infected model mice (GSE13873)19, which develop premalignant lesions such as gastric atrophy, compensatory epithelial hyperplasia and intestinal metaplasia, the expression of TGM2 was significantly increased in hyperplastic and metaplastic lesions compared with uninfected control tissue (Fig. S2). Here, TGM2 is linked to chronic atrophic gastritis.