1. Bone Tumor Reference Center at the Institute of Pathology, University Hospital Basel, Basel, Switzerland
2. Clinical Cooperation Group Osteosarcoma, Helmholtz Zentrum Muenchen - National Research Centre for Environment and Health, Neuherberg, Germany
3. Institute of Pathology, Helmholtz Zentrum Muenchen - National Research Centre for Environment and Health, Neuherberg, Germany
4. Department of Pediatrics, Technische Universitaet Muenchen and Pediatric Oncology Center, Munich, Germany
5. Klinikum Stuttgart Olgahospital, Pediatrics 5 - Oncology, Hematology, Immunology, Stuttgart, Germany