1. Department of Otorhinolaryngology – Head and Neck Surgery, University of Helsinki and Helsinki University Hospital, Helsinki, Finland;
2. Department of Oncology and Research Program Unit, Medical Faculty, University of Helsinki and Helsinki University Hospital Cancer Center, Helsinki, Finland;
3. Department of Pathology, University of Helsinki and Helsinki University Hospital, Haartman Institute, Helsinki, Finland;
4. Division of Ear, Nose and Throat Diseases, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden