EXCITEMENT about the potential of stem cells for curing all manner of ills is being tempered by two new studies that highlight the potential dangers. They show that even stem cells taken from adults can turn cancerous if they are allowed to multiply for too long outside the body.
Researchers have long known that there is a cancer risk with stem cells extracted from very early embryos. Until they change into more specialised tissue, they can form aggressive cancers called teratomas when injected into animals.
Until now, it has been widely assumed that adult stem cells, such as those taken…
