1. Department of Medicine A, Hematology, Oncology and Pneumology University Hospital Muenster Muenster Germany
2. Department of Otolaryngology/Head and Neck Cancer University Hospital Muenster Muenster Germany
3. Department of Pediatrics University Hospital Muenster Muenster Germany
4. Department of Otolaryngology/Head and Neck Cancer University Hospital Ulm Ulm Germany
5. Department of Pediatric Hematology/Oncology University Hospital Muenster Muenster Germany