1. Department of Pathology, University Hospital Muenster, Muenster, Germany
2. Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Muenster, Muenster, Germany
3. Institute of Pathology, University Hospital Cologne, Cologne, Germany
4. Current address: Institute of Pathology, Charité University Hospital Berlin, Berlin, Germany
5. Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Cologne, Cologne, Germany