Somatic cells can be reprogrammed into pluripotent stem cells, called induced pluripotent stem cells (iPSCs), by defined transcription factors (Takahashi et al., 2006). The reprogramming of somatic cells may be a continuous stochastic process in which nearly all somatic donor cells have the ability to give rise to iPSCs with continuous passaging and the expression of defined factors (Hanna et al., 2009). However, the reprogramming process can be divided into discrete stages, including the generation of dedifferentiated pre-pluripotent cells followed by authentic pluripotent cells (Silva et al., 2009). The sequential expression of marker genes, such as AP, SSEA1, and Oct4 or Nanog, has been demonstrated during the reprogramming process (Brambrink et al., 2008). Neural stem cells (NSCs) endogenously express SSEA1 and exhibit AP activity (Kim et al., 2009), suggesting that NSCs are a quasi-intermediate state and might represent a more advanced stage in the reprogramming process compared with terminally differentiated cells. Subsequently, iPSCs have been generated from NSCs using Oct4 alone (Kim et al., 2009).