1. Department of Pediatrics, University Hospital Schleswig-Holstein, Campus Kiel, Germany
2. Pediatric Hematology and Oncology, University Hospital Schleswig-Holstein, Campus Lübeck, Germany
3. Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
4. St. Anna Children's Hospital, Vienna, Austria
5. Kinderspital, University Hospital Zürich, Switzerland