1 Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
2 National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China.
3 Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China. minli@ccmu.edu.cn.
4 National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China. minli@ccmu.edu.cn.