1. Department of Otorhinolaryngology—Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland.
2. Department of Otorhinolaryngology—Head and Neck Surgery and Medical Biochemistry, Turku University Central Hospital, Turku, Finland.
3. Department of Pathology, University of Helsinki, Helsinki, Finland.
4. Department of Pathology, University of Oulu, Oulu, Finland.
5. Nuclear Medicine, Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland.