APC and gastric adenoma: In this setting, both the deletion of the tumor suppressor Adenomatous polyposis coli (Apc) in Lgr5+ cells and the deletion of the GC suppressor Kruppel-like factor 4 (Klf4) in Villin+ cells resulted in the appearance of gastric adenomas [23,27], reflecting that multiple stem/progenitor pools might be susceptible to oncogenic transformation.