Too much of a good thing

Honestly I'm not surprised at this news from Nature:

Parkinson's therapy cures, but has unexpected side effect. It's called brain tumors. Please note this was not a stem cell experiment. They took embryonic early brain cells. So these were not stem cells, but cells already commited to make the brain.

The one good thing about stem cells is their ability to divide, and then those daughter cells can make their own daughter cells. Then eventually they make brain cells, pancreas, heart, and eventually the entire body that is ourselves.

I know that using bone marrow stem cells from heart disease patients and putting them by the damaged sections has had good results. I don't know if in the rat brain experiments they just put too many of these brain cells in. Perhaps they would have better luck with embryonic stem cells.

I'm sure for people like Michael J. Fox will be disappointed in this result. But honestly, this is why animal studies are always done before people. There are safeguards and guidelines on how to treat these animals to cause them the least amount of pain and suffering.