1. Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany;
2. German Cancer Consortium, Freiburg, Germany, and German Cancer Research Center, Heidelberg, Germany;
3. Department of Pediatric Hematology and Oncology, Charles University and University Hospital Motol, Prague, Czech Republic;
4. Department of Pediatrics, Aarhus University Hospital Skejby, Aarhus, Denmark;
5. Department of Pediatric Oncology and Hematology, University of Bologna, Bologna, Italy;
6. St. Anna Children's Hospital and Children's Cancer Research Institute, Medical University of Vienna, Vienna, Austria;
7. Department of Hematology and Oncology, University Children's Hospital, Zurich, Switzerland;
8. Erasmus Medical Center, Rotterdam, and Dutch Childhood Oncology Group, The Hague, The Netherlands;
9. Department of Pediatric Hematology, Oncology, and BMT, Medical University of Wroclaw, Wroclaw, Poland;
10. Department of Pediatric Hematology-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium;
11. Department of Hematology and Oncology, Hospital Sant Joan de Déu, Barcelona, Spain;
12. Paediatric Oncology and Haematology, Our Lady's Children's Hospital Crumlin, Dublin, Ireland;
13. Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands;
14. Pediatric Hematology-Oncology, Fondazione Istituti di ricovero e cura a carattere scientifico (IRCCS) Policlinico San Matteo, Pavia, Italy;
15. Pediatric Oncology, Queen Silvias Children's Hospital, Gothenburg, Sweden;
16. Pediatric Oncology, Charité-University Medicine Berlin, Berlin, Germany;
17. Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany;
18. Department of Pediatric Hematology and Oncology, Dr.v.Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany;
19. Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH;
20. Institute of Pathology, University of Erlangen, Erlangen, Germany;
21. Institute of Human Genetics, Hannover Medical School, Hannover, Germany;
22. Department of Pediatric Hematology and Oncology, Bambino Gesù Children's Hospital, Rome, University of Pavia, Pavia, Italy; and
23. Department of Pathology, Clinical Center, Böblingen, Germany