PROM1 and neoplasm: While 5-FU or cisplatin enriched for a CD133/Prom1+ liver tumor-initiating/propagating cell subset (Fig. 1a and Supplementary Fig. S1a), the genetic depletion of Prom1+ cells, using conditional CreER-induced diphtheria toxin (DTA) crossed with Prom1C-L, resulting in selective Prom1 cell death (Prom1-DTA), sensitized HCC tumors to 5-FU treatment and impeded tumor growth as demonstrated by reduced liver weight (Fig. 1c, d) and number of tumor nodules (Fig. 1e, f), concomitant with a decreased tumor-initiating cell frequency (Fig. 1g).