1. Department of Gastroenterology, Ningxia Hui Autonomous Region People's Hospital, Yinchuan, Ningxia Hui Autonomous Region 750021, P.R. China
2. Department of Gastroenterology, Ankang Central Hospital, Ankang, Shanxi 725000, P.R. China
3. Department of Basic Medicine, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, P.R. China
4. Department of Gasteroenterology, Xijing Hospital of Digestive Diseases, State Key Laboratory of Cancer Biology and Institute of Digestive Diseases, Xi'an, Shanxi 710000, P.R. China