1. Department of Otorhinolaryngology, Head and Neck Surgery Tohoku University Hospital Sendai Japan
2. Department of Otolaryngology Iwate Medical University Morioka Japan
3. Department of General Internal Medicine and Clinical Laboratory Medicine Akita University Graduate School of Medicine Akita Japan
4. Department of Pathology Osaki Citizen Hospital Osaki Miyagi Japan
5. Department of Otolaryngology Tohoku Medical and Pharmaceutical University Sendai Japan