1. Department of Pediatrics; University Medical Center Schleswig-Holstein; Campus Kiel Germany
2. Department of Pathology; Lymph Node Registry Kiel; Institute of Hematopathology University Hospital Schleswig-Holstein; Campus Kiel Germany
3. Department of Pathology; Kiel Pediatric Tumor Registry; Institute of Pediatric Pathology; University Hospital Schleswig-Holstein; Campus Kiel Germany
4. Department of Pediatric Oncology/Hematology; Charit; é; University Medicine; Berlin Germany
5. Division of Pediatric Hematology and Oncology, Department of Pediatrics; Hannover Medical School; Hannover Germany
6. Department of Pediatrics; Klinikum Lippe Detmold; Detmold Germany