Amid the high hopes the stem cell therapies could revolutionize the treatment of a number of diseases, researchers at the University of Rochester and Cornell have made a discovery that has serious implications, both good and bad, for the possibilities of stem cell research. “Researchers…have for the first time essentially cured rats of a Parkinson's-like disease using human embryonic stem cells. But 10 weeks into the trial, they discovered brain tumours had begun to grow in every animal treated,†reports the Globe and Mail. Though the tumours were benign, this is by no means an acceptable side effect. By their very nature stem cells are designed to grow and divide rapidly and scientists have theorized that this could lead to tumour growth. This study proves that theory. Researchers say using a different type of stem cell may not result in tumours, but current policy prevents Health and Human Services-funded labs from using certain stem cells. The findings are published in the current issue of Nature Medicine. Report