PROM1 and colorectal carcinoma: Several studies linked CD133high expression with a high risk of metastasis in CRC patients (LaBarge and Bissell, 2008; Kojima et al., 2008; Horst et al., 2008; Ong et al., 2010; Gallmeier et al., 2011), but the effective value of CD133 as a CSC biomarker is unclear, because, as observed in the SW620 colon cell line, sorted CD133+ and CD133− subsets can undergo conversion between the two subsets (Hsu et al., 2013; LaBarge and Bissell, 2008; Kojima et al., 2008).