1. Department of Pediatric Hematology and Oncology, University Children´s Hospital Muenster, Muenster, Germany
2. Gerhard Domagk Institute of Pathology, University of Muenster, Muenster, Germany
3. University Hospital Essen, Pediatrics III, West German Cancer Centre, Essen, Germany
4. Institute of Biostatistics and Clinical Research, University of Muenster, Muenster, Germany
5. Department of Orthopedic Surgery, University Hospital Muenster, Muenster, Germany
6. Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Muenster, Germany