1. 1Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
2. 2Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
3. 3Department of Internal Medicine/Clinical Immunology, Erasmus Medical Center (Erasmus MC), Rotterdam, The Netherlands
4. 4Children’s Cancer Research Institute, St Anna Kinderkrebsforschung, Medical University of Vienna, Vienna, Austria
5. 5Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
6. 6Cergentis BV, Utrecht, The Netherlands
7. 7Pediatric Hematology/Oncology Department, Meyer Children’s University Hospital, Florence, Italy
8. 8Department of Pathology, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
9. 9Department of Pathology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
10. 10Department of Pathology, University Medical Center Groningen, Groningen, The Netherlands
11. 11Department of Pathology and Molecular Medicine, Second Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
12. 12Department of Pathology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
13. 13Department of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
14. 14Childhood Cancer Research Unit, Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
15. 15Department of Pediatric Oncology, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
16. 16Department of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
17. 17Department of Pediatric Oncology, Sophia Children’s Hospital, Erasmus MC, Rotterdam, The Netherlands
18. 18Department of Immunology, Erasmus MC, Rotterdam, The Netherlands
19. 19Department of Hematology/Oncology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
20. 20Department of Pediatric Oncology, Emma Children’s Hospital, Amsterdam University Medical Centers, Amsterdam, The Netherlands