摘要
Embryonic stem cells derived from the inner cell mass of blastocyst stage embryos （ES cells） are capable of differentiating into any cell type, offering the possibility of their use in cell transplantation therapies. However, the risk of rejection by the immune system and the bioethical issues inherent to the use of embryonic cells prompted the search for a mechanism of obtaining pluripotent cells from adult cells and thus, potentially self tissues. In 2006, Takahashi and Yamanaka succeeded in reprogramming adult fibroblasts to induced pluripotent stem cells （iPSCs） by the forced expression of four transcription factors,
