[1] German Canc Res Ctr, Heidelberg, Germany
[2] NN Burdenko Inst Neurosurg, Moscow, Russia
[3] Univ Hosp Dusseldorf, Dusseldorf, Germany
[4] Hosp Sick Children, Toronto, ON M5G 1X8, Canada
[5] Univ Hosp Munster, Munster, Germany
[6] Univ Munich, Munich, Germany
[7] Max Planck Inst Mol Genet, D-14195 Berlin, Germany