1. Department of Surgery, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Korea
2. Department of Pathology, Ulsan University Hospital, Ulsan, Korea
3. Department of Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
4. Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea