iPS cell

I guess that the discovery of iPS cell will be nominated a Nobel Prize in the near future.

Recently, Dr. Yamanaka and colleagues succeeded in generating mouse iPS cells without viral vectors and reported the results in the Science.
(http://www.sciencemag.org/cgi/content/abstract/1164270v1)
Usually iPS cells are produced by induction of four genes, namely, Oct3/4, Sox2, Klf4, and c-Myc, using retroviral vectors. However, the integration of viral sequences into the host genome increases the risk of tumorigenicity. The researchers showed that repeated transfection of a plasmid containing three genes (i.e. Oct3/4, Sox2, and Klf4) and a c-Myc expression plasmid into embryonic fibroblasts resulted in iPS cells without plasmid integration into genome.

On the other hand, Dr. Melton and colleagues reported in the Nature Biotechnology that valproic acid, a histone deacetylase inhibitor, enables reprogramming of primary human fibroblasts with only two factors, Oct4 and Sox2.
(http://www.ncbi.nlm.nih.gov/pubmed/18849973)
Maybe these remainder genes can be substituted by chemical compound(s) too.

In another report, Belmonte et al. succeeded in generating iPS cells from single adult human hairs.
(http://www.ncbi.nlm.nih.gov/pubmed/18931654)

Research on iPS cell is getting more and more competitive. For the discovery of HIV, Dr. Montagnier but not Dr. Gallo won the 2008 Nobel Prize in Medicine. I believe that Dr. Yamanaka will win the Prize for the discovery of iPS cell.