CSCs express specific cell surface markers, including cluster of differentiation 133 (CD133), CD44, aldehyde dehydrogenase-1 (ALDH-1), and leucine-rich repeat-containing G-protein coupled receptor-5 (Lgr-5), and these are also expressed in CRC [10,11,12,13]. The gene discussed is ALDH1A1; the disease is colorectal carcinoma.