1. Kiel Pediatric Tumor RegistryDepartment of PathologySection of Pediatric PathologyUniversity of Kiel Kiel Germany
2. Department of Pediatric Hematology and OncologyUniversity of Bonn Bonn Germany
3. Department of PathologyUniversity of Bonn Bonn Germany
4. Department of PathologyHematopathology Section and Lymph Node RegistryUniversity of Kiel Kiel Germany