AFP and neoplasm: The apparently paradoxical relative decrease of NANOG transcript abundance in tumor tissues compared with NTL ones maybe be attributed either to a large excess of NANOG biosynthesis by proliferative endothelial cells in normal hepatic tissue, or to an aberrant state of differentiation of the tumor cells that retains a decayed stem cell phenotype together with the expression of endodermal lineage markers, such as AFP [66], [67].