Stem Cells Linked to Cancer Risk

Some medical researchers may be moderating their optimism with the news that stem cells replicated in the laboratory have produced aggressive cancers when transplanted into animals. The likelihood of creating cancerous cultures is tied directly to the amount of time cell division occurs in the laboratory. Stem cells that are allowed to age longer outside the body are thought to produce an enzyme, telomerase, which overrides the cells' ability to limit the number of times they divide. The finding is not a deal-breaker, though. Evidence suggests that adult stem cells are safe if the number of times they are allowed to divide outside the body is limited.

Research teams at the Autonomous University of Madrid in Spain and the University Hospital of Odense in Denmark are credited with discovering the stem cell-cancer link. Unfortunately, it's likely to slow progress on current stem cell projects while tempering the tunnel vision of the most enthusiastic researchers. Certainly, everyone will hurry up to go a bit slower.