Candidate markers for CRC MetSC characterization include CD166, CD29, CD24, LGR5, EpCAM (CD326), ALDH1, CDCP1, CXCR4, CC188 (Hsu et al., 2013; Pitule et al., 2014) and ephrin type B receptor 2 (EphB2) (Rowehl et al., 2014), although many of these markers are also expressed in normal colonic stem cells (i.e. LGR5, ALDH1, or CD29), complicating the distinction between CSCs and normal stem cells. Here, ALDH1A1 is linked to colorectal carcinoma.