1. Pediatrics 5; Klinikum Stuttgart; Olgahospital Stuttgart Germany
2. Department of Pediatric Pathology, Kiel Pediatric Tumor Registry; University Hospital of Schleswig-Holstein; Campus Kiel Germany
3. Department of Pediatric Hematology/Oncology and BMT; University of Wroclaw; Wroclaw Poland
4. Department of Pediatric Oncology; University of Zurich; Zurich Switzerland
5. St. Anna Kinderspital and St. Anna Kinderkrebsforschung e.V; Vienna Austria
6. Department of Pediatric Hematology and Oncology; University Children's Hospital Muenster; Münster Germany
7. Hospital for Children and Adolescents; Goethe-University Frankfurt; Frankfurt am Main Germany
8. Department of Pediatric Oncology; University of Tuebingen; Tuebingen Germany