The University of Wisconsin-Madison researchers who turned ordinary skin cells into stem cells in 2007 have cleared a major safety concern of using those cells in research: their risk of cancer. Their previous process used a virus to insert several genes into the DNA of skin cells. The genetic code of these genes naturally reprograms cells to revert to their original stem cell state. There was just one problemthe new stem cells were cancer-prone.
The team's new method uses a different vehicle to insert the reprogramming genes: a ring of DNA called a plasmid. Plasmids don't integrate into the DNA of the adult cells, but instead float independently in the nucleus. Still, they still signaled the switch to stem cells. This fact, plus the advantage that the plasmids could be removed after their work was done, likely helped clear the cancer risk.
The University of Wisconsin will soon make the new stem cells available to researchers worldwide to investigate their utility in understanding and treating disease.