Enhanced efficiency of generating induced pluripotent stem （iPS） cells from human somatic cells by a combination of six transcription factors

Dear Editor, Human embryonic stem （ES） cells possess the potential to differentiate into all the cell types of the human body and provide potential applications in regenerative medicine . However, the concerns of immune rejection hamper transplantation therapies using human ES cells. To avoid the complications of immune rejection, diverse methods, such as somatic nuclear transfer （also called therapeutic cloning） and fusion of somatic ceils with human ES ceils , have been attempted to produce patient-specific pluripotent stem cells. Most of these approaches have resulted in little success. The generation of human iPS cells （induced