1. Department of Otorhinolaryngology-Head and Neck Surgery, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
2. Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea.
3. Department of Urology, Korea University College of Medicine, Seoul, Korea.
4. Department of Pathology, Korea University College of Medicine, Seoul, Korea.
5. Department of Respiratory Internal Medicine, Korea University College of Medicine, Seoul, Korea.