1. Department of Surgery, Kyung Hee University School of Medicine, Seoul, Korea.
2. Research Institute and Hospital, National Cancer Center, Goyang, Korea.
3. Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
4. Department of Surgery, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.
5. Chung-Cheong Surgery Clinic, Daejeon, Korea.
6. Department of Surgery, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.