[Stitcher]

WebMD: Health News

New Debate on Human Test of Stem Cells

Scientists Wrestle With Risks and Benefits of Implanting Stem Cells in People

By Todd Zwillich
WebMD Medical News
Reviewed by Brunilda Nazario, MD

April 10, 2008 -- While politicians battle over where to set limits for human embryonic stem cell studies, regulators are mulling where it should set scientific limits on the promising but controversial research.

Despite widespread media coverage, embryonic stem cells and related cells have only been implanted in a handful of human patients. Researchers say some of the experiments have shown early signs of success. Others have been failures because they were ineffective or led to tumors.

Most research is still conducted in Petri dishes and animals like rats and pigs. But with the field on the brink of producing new therapies for humans, how to test those treatments -- and how much risk to tolerate -- remain open questions.

Stem cells' scientific promise lies in their ability to form dozens of different tissues in the body. As these cells divide and grow, they can be coaxed to form heart, lung, brain, or pancreatic cells. That makes them good candidates to engineer new tissues to repair diseases or injuries.

But their potential may also be a curse. Because embryonic stem cells are genetically programmed to easily divide and grow, research shows they also have the propensity to form tumors.

READ more