1. Department of Internal Medicine, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
3. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Science, Seoul, Korea.