Characterization of immortalized MSC-derived hepatocyte-like cells. The TERT/Bmi-1-transduced MSCs had been differentiated into hepatocyte-like cells. The differentiated cell had polygonal shape, granulated cytoplasm and large nucleus (A). After the next passage, the cytoplasmic/nucleolus ratio was further decreased with loose intercellular attachment (B). The glycogen storage activity was demonstrated using Periodic Acid Schiff staining (PAS) with greater than 95% of the population were positive for glycogen (C). After the maintenance in DMEM/F12, 10% FBS in subsequent passages, cells were densely packed with closer intercellular attachment (D). After reaching confluence, cells formed duct-like structure (E). The life span of the immortalized hepatocyte-like cells was beyond 3 months (F) with active division.