Since the Lgr5 knock-in allele shows mosaic expression in the Lgr5-EGFP-IRES-CreERT2 mouse model44, we also induced tumours using the Apcloxp/loxp: Villin-CreERT2 mouse model, which results in Apc loss in all intestinal epithelial cells, including ISCs, with tamoxifen administration (Fig. 5f). Here, LGR5 is linked to neoplasm.