1. Institution for Digestive Research, Digestive Disease Center, Department of Internal Medicine, Soonchunhyang University Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.
2. Department of Obstetrics and Gynecology, Soonchunhyang University College of Medicine, Seoul, Korea.
3. Department of Pathology, Soonchunhyang University College of Medicine, Seoul, Korea.