1. Department of Otorhinolaryngology, Head and Neck Surgery; University of Cologne Medical Centre; Cologne Germany
2. Department of Pathology; University of Cologne Medical Centre; Cologne Germany
3. Jean-Uhrmacher Institute for Otorhinolaryngological Research; Cologne Germany
4. Department of Radiation Therapy; University of Cologne Medical Centre; Cologne Germany
5. Department of Otorhinolaryngology, Head and Neck Surgery; University of Giessen; Giessen Germany