1. Department of General Pediatrics, Hematology and Oncology, Children's University Hospital Tübingen, Tübingen, Germany
2. Memorial Sloan Kettering Cancer Center, Center for Cell Engineering, New York, NY, USA
3. Dr. von Hauner Children's Hospital, Ludwig Maximilians University Munich, Munich, Germany
4. Institute of Pathology, University Hospital Tübingen, Tübingen, Germany