NANOG and colorectal carcinoma: CSC stemness has been characterized by the expression of pluripotency-associated stemness transcriptional factors, typically KLF4, c-MYC and NANOG [40,41], while Western blot and qRT-PCR analysis indicated up-regulated expression of these stemness factors in the spheroid cells relative to the parental CRC cells; the up-regulation was reversed in the serum-induced differentiated cells (Figure 2B,C), consistent with spheroid culture-dependent stemness enrichment.