1. Department of Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Cancer Research Institute, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Surgery, Myongji Hospital, Goyang, Korea.
4. Department of Surgery, Gachon University Gil Medical Center, Incheon, Korea.
5. Department of Surgery, Seoul National University Boramae Medical Center, Seoul, Korea.