1. Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital Ostrava, 17. Listopadu 1790, 70852 Ostrava, Czech Republic
2. Department of Pathology, University Hospital Ostrava, 17. Listopadu 1790, 70852 Ostrava, Czech Republic
3. Faculty of Medicine, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic