1 Gastroenterology and Hepatology Unit, Gastrointestinal Endoscopy Unit, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
2 Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Sha Tin, Hong Kong.
3 State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Sha Tin, Hong Kong.