Stem Cell Work Shows Promise and Risks: Parkinson's Treatment Tried in Rats Reduced Symptoms but Caused Tumors - Washington Post
Nerve cells grown from human embryonic stem cells and injected into the brains of rats with a syndrome mimicking Parkinson's disease significantly reduced the animals' symptoms, but the treatment also caused tumors in the rodents' brains, scientists reported yesterday.

Researchers said the work showed both the potential benefits and risks of human embryonic stem cells, which have been highly touted for their capacity to replace diseased tissue but are controversial because they are derived through the destruction of human embryos.

"The behavioral data validate the utility of the approach. But it also raises a cautionary flag and says we are not ready for prime time yet," said lead researcher Steven A. Goldman, a professor of neurology and neurosurgery at the University of Rochester Medical Center.

Goldman said he suspected that with modest changes in technique, researchers will be able to keep the benefits of the treatment while eliminating or reducing the chances of getting the cancerlike growths. But he conceded that much more basic research would have to be done before scientists -- or regulators -- were likely to be convinced of the approach's safety.MORE- Washington Post