1. Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China
2. Department of General Surgery, Beijing YouAn Hospital, Capital Medical University, Beijing, China
3. Department of Gastroenterology and Hepatology, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
4. Department of Gastroenterology and Hepatology, People's Hospital of Hetian, Hetian, Xinjiang, China