1. Saarland University Hospital, Pediatric Hematology and Oncology, Homburg/Saar, Germany
2. Dep. of Biometry, Epidemiology and medical Informatics, Saarland University, Homburg, Germany
3. Paidopathology, Schleswig Holstein University Hospital, Campus Kiel, Kiel, Germany
4. Paidopathology, Vienna University, Vienna, Austria
5. Diagnostic Radiology, Division of Pediatric Radiology, Heidelberg, Germany
6. Children’s Hospital, University Hospital, Zurich, Switzerland
7. Pediatric Hematology and Oncology, St. Anna Forschungspital, Vienna, Austria
8. Pediatric Surgery, LMU Hospital, München, Germany