NANOG and neoplasm: When we counted the cells in the immunofluorescent images of the tumor tissues around necrotic areas, SOX2+ HIF-1α+ RNApII-S2P-/low cells and NANOG+ HIF-1α+ RNApII-S2P-/low cells accounted for 0–6.3% and 0–4.7% of the cells in the microscopic field, respectively.