[1] German Canc Res Ctr Heidelberg, Div Mol Genet, Heidelberg, Germany
[2] Univ Heidelberg Hosp, Dept Pediat Oncol Hematol & Immunol, Heidelberg, Germany
[3] Univ Dusseldorf, Dept Neuropathol, D-4000 Dusseldorf, Germany
[4] Univ Heidelberg Hosp, Dept Neuropathol, Heidelberg, Germany