Characterization of induced pluripotent stem cells generated from human gingival fibroblasts (HGF-iPSCs). (A) Quantitative RT-PCR of four HGF-iPSCs, 1-1 (passage 25), 1-2 (passage 20), 1-3 (passage 21), and 1-4 (passage 20), of pluripotency-related gene expression (OCT3/4, NANOG, SOX2, KLF4, REX1, CMYC, TERT, and DPPA5). KhES-1 cells (passage 23) were used as positive control and human gingival fibroblasts (HGFs) (passage 6) as negative control were used; (B) Expression of episomal vector transgenes in human HGF-iPSCs, HGFs (passage 6) as negative control, and HGFs on day 1 after transduction (TF d1) with episomal vectors as positive control. QRT-PCR data represent mean ± standard deviation (SD) of three independent experiments; (C) Growth curve of four HGF-iPSCs; (D) Morphology of HGF-iPSCs 1-1 cultured on SNL feeder (passage 26). Established HGF-iPSC line 1-1 was stained to identify any ALP activities and for OCT3/4, NANOG, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. Scale bar = 400 μm; (E) Karyotype analysis of iPSCs 1-1 at passage 26 by G-band staining.