1 Division of Paediatric Haematology and Oncology, Department of Paediatrics, Obstetrics, and Gynecology, University Hospital of Geneva, Geneva 1211, Switzerland. Electronic address: andre.vonBuren@hcuge.ch.
2 Institute of Neuropathology, University Medical Center Hamburg Eppendorf, Hamburg, Germany.
3 Department of Paediatric Haematology and Oncology, University Medical Center Hamburg Eppendorf, Hamburg, Germany.