1. Department of Internal Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam;
2. Department of Gastroenterology, Gia-Dinh People’s Hospital, Hochiminh City, Vietnam;
3. Health Service Center, Hiroshima University, Higashihiroshima, Japan;
4. Department of Surgical Pathology, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam;
5. Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan