We are in the early and rapidly changing stage in Induced Pluripotent Stem (iPS) cell development. Until now, most research effort has been directed toward finding a way to introduce genes into an adult cell in order to return it to an embryonic stem cell state.
The step that isn't talked about much is the next one: after the cell is returned to an embryonic state it must then be coaxed or directed to become the type of cell needed in the therapeutic process or application. The holy grail of Induced pluripotent stem cell development would be to change an abundant adult cell into the type of cell needed in the patient's body. And the holiest of all grails would be to do it without removing the cell from the patient.