OUTLINE: This is a multicenter study. Patients are stratified according to tumor type (high-grade glioma [closed to accrual as of 4/21/2009] vs intrinsic brain stem tumor [closed to accrual as of 4/21/2009] vs medulloblastoma [closed to accrual as of 10/27/2010] vs ependymoma [closed to accrual as of 7/29/2010] vs low grade glioma [closed to accrual as of 7/29/2010]).