Stem cell 'cure' boy gets tumour

A boy treated with foetal stem cells for a rare genetic disease has developed benign tumours, raising questions about the therapy's safety.

The boy, now 17, received the stem cells in 2001 at a Moscow hospital and four years later scans showed brain and spinal tumours, PLoS Medicine reports.

Israeli doctors removed the abnormal growth from his spine and tests suggest it sprouted from the stem cells.

Critics say the finding is evidence against the controversial therapy.

Apart from the ethics of using cells taken from embryos, opponents say there are big safety concerns.

As well as the possibility that stem cells may turn cancerous, some researchers fear that it is possible that stem cell therapy could unwittingly pass viruses and other disease causing agents to people who receive cell transplants.

Experimental therapy

Experts are hopeful that stem cells, which have the ability to develop into other kinds of human cells, will eventually lead to treatments for some of the most intractable conditions.

The boy in question was treated for a condition called Ataxia Telangiectasia - a genetic disease that...