LGR5 and colorectal cancer: In a mouse model for colorectal cancer with the Lgr5 promoter driving the expression of diphtheria toxin receptor (DTR) to allow the controllable ablation of Lgr5+ cells, de Sousa e Melo et al. reported that the selective ablation of Lgr5+ CSCs with the addition of diphtheria toxin stopped tumor growth without tumor regression [167,168].