Comment on breaking research in Cell and Science

November 20, 2007 - This research seems to be very well done and follows on the heels of similar work by the Yamanaka laboratory in mouse cells that was independently confirmed by other laboratories. The discovery that it is possible to reprogram adult human cells to pluripotency using a simple combination of genes is an important breakthrough.

This work will likely have an important impact but it is too soon to know whether this approach will replace the derivation of embryonic stem cells from embryos or by nuclear transfer. More work must be done with these de-differentiated cells to determine how stable they are and whether they really are functionally equivalent to embryonic stem cells. Most importantly, the use of viruses to transport the reprogramming genes into the adult human cells causes mutations that predispose these cells to cancer. This technical problem will have to be solved before the de-differentiated cells can be used clinically. Until this is done, it is premature to suggest that these cells can replace the use of ES cells derived from embryos. Research must continue on ES cell lines derived from embryos, as well as nuclear transfer, while this alternative approach is further developed.

Sean Morrison
Investigator, Howard Hughes Medical Institute
Henry Sewall Professor in Medicine
Director, Center for Stem Cell Biology
University of Michigan