1. Department of Otorhinolaryngology, Head and Neck Surgery; Kantonsspital St. Gallen; Switzerland
2. Department of Otorhinolaryngology, Head and Neck Surgery; University Hospital Zurich; Switzerland
3. Clinical Trials Unit; Kantonsspital St. Gallen; Switzerland
4. Department of Clinical Pathology; University Hospital of Zurich; Switzerland
5. Institute of Pathology, Kantonsspital St. Gallen; Switzerland