Stem cells hold the remarkable capacity of self-renewal and differentiation into more specialized cell lineages,and thus constitute a promising resourcein regenerative medicine for the generation of appropriate cell types in cell replacement therapy.Stem cell research,accordingly,has become a highly vigorous and rapidly evolving field in life sciences,highlighted by the 2012Nobel Prize in Physiology or Medicine awarded to Shinya Yamanaka and John Gurdon,for their ground-breaking works in reprogramming cell fates [1].