(A) CD34⁺ (green) or CD34^– (red) esophageal epithelial cells were CK⁺ (94.8% ± 1.66% or 91.24% ± 1.38% by FACS, respectively; data not shown), and nuclei were stained with DAPI (blue). Original magnification, ×1,000. Scale bars: 5 μm. (B) Comparison of selected markers (CD34, ABCG2, EphA3) in SP cells normalized to NSP cells by RT-PCR (*P < 0.01 compared with NSP; n = 3 experiments). (C) Comparison of selected markers in CD34⁺ cells normalized to CD34^– cells by RT-PCR (*P < 0.01 compared with CD34^–; n = 3 experiments). In B and C, data are mean ± SEM. (D, G, and J) PBS (control) was injected in the submucosa after mucosal injury. The epithelium reformed after 48 hours. There were no GFP⁺ cells (red) in PBS-injected tissues. (E, H, and K) CD34^–GFP⁺ cells (3 × 10⁴) were injected into the submucosa after induction of mucosal injury. The epithelium re-formed after 48 hours. There were few GFP⁺ cells (red) in the epithelium. (F, I, and L) CD34⁺GFP⁺ cells (3 × 10⁴) were injected into the submucosa after induction of mucosal injury. The epithelium re-formed after 48 hours. The re-formed epithelium was GFP⁺, consistent with the migration of stem cells and emergence of differentiated lineages. Some GFP⁺ cells remained in the submucosa. Arrowheads indicate basement membrane. Arrows indicate site of cell injection in the submucosa. Original magnification, ×40 (D–F); ×100 (G–L). Scale bars: 25 μm.