1. Department of Gastroenterology, Hangzhou First People's Hospital, Nanjing Medical University, Hangzhou, China
2. Departmemt of Gastroenterology, Beijing Tsinghua Changgung Hospital Medical Center, Tsinghua University, Beijing, China
3. Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China