Recently, we worked all the way from isolation of skin fibroblasts of PD patients and control individuals, to the generation of iPS cells by retrovirus-mediated expression of OCT4, SOX2, c-MYC and KLF4, to the differentiation of iPS cells to neural stem cells (NSC) and DA neurons, and finally to the transplantation of the iPS cells-derived NSCs to the striatums of the 6-OHDA-induced PD rats. The gene discussed is KLF4; the disease is Parkinson disease.