1. Department of Pediatric Oncology/Hematology; VU University Medical Center; Amsterdam The Netherlands
2. Department Of Hematology; VU University Medical Center; Amsterdam The Netherlands
3. Department Of Biology; Technion-Israel Institute of Technology; Haifa Israel
4. Department Of Rheumatology; VU University Medical Center; Amsterdam The Netherlands
5. Department Of Medical Oncology; VU University Medical Center; Amsterdam The Netherlands
6. Dutch Childhood Oncology Group (DCOG); The Hague The Netherlands