1. Department of Internal Medicine and Pediatrics, Ghent University, Belgium
2. Department of Pediatric Hematology-Oncology and Stem Cell Transplantation, Ghent University Hospital, Belgium
3. Cancer Research Institute Ghent, Belgium
4. Department of Pediatric Hematology and Oncology, University Hospitals Leuven, Department of Oncology, KU Leuven, Belgium