1. Department of Pediatric Hematology and Oncology; Hannover Medical School; Hannover Germany
2. Department of Pediatric Hematology and Oncology; University Hospital for Children and Adolescents; Friedrich Schiller University; Jena Germany
3. Department of Hematology and Oncology; University of Leipzig; Germany
4. Department of Pediatric Hematology/Oncology; University Hospital of the Saarland; Homburg Germany