The Yamanaka team announced in a Science paper today that it was able to induce pluripotency in cells taken from the liver and intestinal lining of mice — and in the process they found that the retroviruses used to turn the cells pluripotent don’t have to insert themselves at specific sites in the cells’ DNA. That opens the window for possibly getting the retrovirus to insert the necessary genes (or “factors” as scientists call them) at places in the cells’ DNA that aren’t associated with tumor growth.*

The risk of iPS cells turning cancerous is one of the big obstacles to the cells being used therapeutically. And if scientists can’t figure out how to solve that problem, it becomes much less likely the cells will eventually be used that way.

Speaking of Yamanaka, the LA Times reports that he’s become a huge celebrity in Japan, somewhat to his annoyance.

-Greg Dahlmann

*Quick review: there’s concern iPS cells could turn cancerous because the retroviruses used to insert the genes necessary for inducing pluripotency can also cause errors in the cells’ DNA, which in turn can cause tumors.