1. Department of Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
3. Division of Surgery, Thyroid Center, Seoul National University Cancer Hospital, Seoul, Korea.
4. Department of Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
5. Department of Surgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.