1. Department of Gastroenterology, Chongqing Key Laboratory of Digestive Malignancies, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing 400042, P. R, China
2. Department of Gastroenterology, People’s Hospital of Chongqing Banan District, Chongqing, China
3. Department of Gastroenterology, The 13th People’s Hospital of Chongqing, Chongqing, China
4. Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, China
5. Department of Gastroenterology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
6. Department of Gastroenterology, Chongqing Red Cross Hospital, Chongqing, China
7. Department of Gastroenterology, Guizhou Provincial People’s Hospital, Guiyang, China