Stem cell marker genes expression and sphere formation. (RT-PCR and sphere formation). (A) RT-PCR of stem cell marker genes OCT 3/4, NANOG, SOX2, and KLF4. Lane 1, freshly isolated HAE cells (fHAE cells); lane 2, HAE cells cultured at passage 1 (HAE cells p1); lane 3, HAE cells cultured at passage 2 (HAE cells p2); lane 4, iHAE A; lane 5, iHAE B; lane 6, negative control. G3PDH mRNA was used as an internal control. (B) iHAE cells made spheroid bodies after they were cultured on ultra-low- attachment dishes for 3 days. Scale bar, 100 μm.