Induced Pluripotent Stem Cells : It Looks Simple but Can Looks Deceive?

Less than a decade ago the prospect for reprogramming the human somatic cell looked bleak at best. Despite the incisive studies of the previous forty years that included demonstrations by Briggs and King and Gurdon of the apparent reversibility of the differentiated state of simpler organisms such as the frog Rana Pipiens and the cloning of “Dolly” it seemed that the only methods at our disposal for the generation of human isogenic pluripotent cells would have to involve somatic cell nuclear transfer (SCNT, for an in depth review refer to 1). This procedure was technically demanding and inefficient in animals and was known to produce offspring of less than optimal quality when used for reproductive cloning but perhaps more importantly it had never been successfully applied to humans. In 2005, the first human embryo derived by SCNT was reported by our group [2] and this has been supplemented by the data of two other groups [3, 4] in the following few years but to date none of these have been successful in deriving the necessary embryonic stem cells (ESC) from such embryos. So what were we to do?