1. Department of Internal Medicine, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, Korea.
2. Department of Pathology, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, Korea.
3. Department of Otorhinolaryngology–Head and Neck Surgery, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, Korea.
4. Department of Surgery, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, Korea.
5. Department of Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea.