Directly Reprogrammed Fibroblasts...

Cell Stem Cell , Vol. 1, No. 1. , pp. 55-70, doi:10.1016/j.stem.2007.05.014 Ectopic expression of the four transcription factors Oct4, Sox2, c-Myc, and Klf4 is sufficient to confer a pluripotent state upon the fibroblast genome, generating induced pluripotent stem cells.

http://www.citeulike.org/user/racheldoyle/article/7661734