NANOG and cancer: Based on the protein expression patterns of iPSC markers OCT4, SOX2, NANOG, KLF4 and c-MYC, we have demonstrated the presence of two unique subpopulations of CSCs in primary colon adenocarcinoma (CA): an epithelial subpopulation expressing NANOG, SOX2 and KLF4, and a stromal subpopulation expressing OCT4, SOX2 and c-MYC [16].