1. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
2. Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea
3. Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
4. Division of Gastroenterology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea