LGR5 and neoplasm: In addition, Mariko et al. used tamoxifen to induce LGR5 gene silencing in LGR5-cre mice and later discovered that ablation of LGR5+ tumor stem cells that were isolated from these mice and xenotransplanted into other mice induced tumor regression, but the reappearance of LGR5+ tumor stem cells induced tumor regrowth (Fig. 5d).