POU5F1 and neoplasm: Diaminobenzidine and immunofluorescent (IF) IHC staining demonstrated the presence of (1) an EMA+/CD44+/SOX2+/SALL4+/OCT4+/pSTAT3+/NANOG+ CSC subpopulation within the tumor nests; (2) an EMA−/CD44−/CD34−/SOX2+/OCT4+/pSTAT3+/NANOG+ subpopulation within the stroma between the tumor nests; and (3) an EMA−/CD44−/CD34+/SOX2+/SALL4+/OCT4+/pSTAT3+/NANOG+ subpopulation on the endothelium of the microvessels within the stroma.