Establishment of single-colony-derived DFCs.

<p>(A). Clone forming of DFCs. Limiting dilution was used for single clone selection. One single cell was observed after the procedure (a), several days later the cells formed a clone in which more than 50 cells were observed (d). (B). Morphological change of DFCs after several passages. (a). At passage 3, DFCs were fibroblast-like cells. (b). Cells became flat after more than 5 passages.