WEDNESDAY, Feb. 18, 2009 (HealthDay News) -- The first case of tumors developing in someone receiving human fetal stem cell therapy has been reported in Moscow, though scientists speculate that the person's disease might have contributed to the growths.
The tumors appeared along the brain and spine of a boy about four years after he began receiving the neural fetal stem cell treatment for a rare neurodegenerative disease, ataxia telangiectasia, that also weakens the immune system. Israeli researchers from Sheba Medical Center in Tel Aviv studied the surgically removed spinal cord tumor, which was benign, and found that it differed genetically from the boy's own tissue.
Rodents injected with pluripotential embryonic stem cells, which are capable of differentiating into various cell types, reportedly have developed tumors, the researchers noted, but the risk was always considered low, especially if the cells were differentiated before injection.
Writing in the February issue of the journal PLoS Medicine, the Israeli team said that the use of stem cell therapy should continue but that the incident points to the need for caution. The finding also warrants further research into the biology of stem cells and their use and safety, "to maximize the potential benefits of regenerative medicine while minimizing the risks," the team wrote.
There's more on stem cells at the U.S. National Institutes of Health.