1. From the Departments of Orthopaedic Surgery, Pediatric Haematology and Oncology, and Medicine/Hematology and Oncology, Westfälische Wilhelms-University, Münster; Department of Orthopaedic Surgery, University of Heidelberg, Heidelberg; Departments of Bone Pathology, Pediatric Oncology, and Radiotherapy, University Hospital Hamburg-Eppendorf, Robert-Rössle-Klinik, Berlin; Cancer Center, Ulm, Germany; Department of Orthopaedics, Balgrist, Department of Pathology, University Hospital of Zürich, Switzerland;...