1. Department of Pediatric Hematology and Oncology; Justus Liebig University Giessen; Giessen Germany
2. Department of Internal Medicine; Stauferklinikum Schwaebisch Gmuend; Mutlangen Germany
3. The Child and Youth Clinic; Department of Pediatric Hematology and Oncology; University Hospital Copenhagen; Copenhagen Denmark
4. Department of Pediatric Hematology and Oncology; Charles University and University Hospital Motol; Prague Czech Republic
5. Department of Pediatric Hematology and Oncology; Eberhard Karls University Tuebingen; Tuebingen Germany
6. Department of Pediatric Hematology and Oncology; University Hospital Ulm; Ulm Germany
7. Children's Hospital Cottbus; Cottbus Germany