 Another purpose of this study is to measure the concentration of drug in the blood to help understand how much drug gets into the body and how quickly the drug is removed from the body. Another purpose of this study is to determine whether MEK162 turns off the RasRafMAP pathway as expected by measuring this pathway in blood cells. Finally, in this study, the investigators hope to start finding out whether or not MEK162 causes different types of tumors in children to shrink or stop growing. 