1 Department of Internal Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam drquachtd@gmail.com.
2 Department of Gastroenterology, Nhan Dan Gia Dinh Hospital, Ho Chi Minh City, Vietnam.
3 Health Service Center, Hiroshima University, Higashihiroshima, Japan.
4 Department of Internal Medicine, Pusan National University School of Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
5 Department of Gastroenterology, Cancer Institute Hospital, Tokyo, Japan.
6 Department of Internal Medicine, Division of Gastroenterology, Jichi Medical University, Shimotsuke, Tochigi, Japan.