Shortly after Ricci-Vitiani et al. (2007) demonstrated the use of the CD133 to identify CSCs in colon tumor, Shmelkov et al. demonstrated that CD133 expression was not restricted to colon CSCs, but that CD133 is expressed on differentiated colonic epithelium in both mice and humans [16, 20]. The gene discussed is PROM1; the disease is colonic neoplasm.