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