Characterization of induced pluripotent stem cell lines (iPSCs). A, B: iPSC lines generated from fibroblasts exhibited typical ESC morphology by phase contrast microscopy (A) and maintained a normal karyotype (B). C: iPSCs strongly expressed the pluripotency marker alkaline phosphatase, whereas the surrounding MEFs were negative. D: Hematoxylin and eosin staining of teratomas derived from iPSC lines confirmed pluripotency by the presence of tissues representing the three major germ layers: ectoderm, endoderm, mesoderm. Scale bars: 100 μm.