APC and gastric cancer: Gastric Lgr5+ stem cells not only regenerate gastric glands at steady state and after tissue damage, respectively, but also, upon oncogenic insult, may serve as cells of origin of advanced gastric cancer in mice; such experimentally induced gastric cancers, or their precursor lesion “spasmolytic polypeptide-expressing metaplasia” (SPEM), can be driven by KrasG12D expression alone (Leushacke et al, 2017) or in conjunction with Apc and Trp53 ablation (Fatehullah et al, 2021).