CSCs were eliminated thanks to the expression of diphtheria toxin receptor [128] or non-dimerized Caspase9 [129] under the control of the promoter for the intestinal stem cell specific gene Lgr5. However, tumor growth resumed after the treatment, and the authors hypothesized that this reappearance was due to dedifferentiation of tumor cells, as already observed in healthy intestine, leading to recovery of tumoral growth. The gene discussed is LGR5; the disease is neoplasm.