These observations are supported by qRT-PCR using TG or NTG cells isolated by FACS, which show that ALDH1A1 is the predominant cytoplasmic ALDH enzyme in colorectal tumors and its expression is further increased in residual tumor cells following therapy with CPA; consistent with the phenotypic increase in ALDH+ cells among the CoCSC phenotype. Here, ALDH1A1 is linked to colorectal neoplasm.