1. Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P. R. China
2. Department of Gastroenterology, The First Affiliated Hospital of Medical College, Shihezi University, No.107 North 2nd Road, Shihezi 832008, P. R. China
3. National Health Commission Key Laboratory of Central Asia High Incidence Disease Prevention and Control, No.107 North 2nd Road, Shihezi 832008, P. R. China
4. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Endoscopy Center, Peking University Cancer Hospital & Institute, Beijing 100142, P. R. China
5. Department of Gastroenterology, Lanzhou Second People’s Hospital, 388 Jingyuan Road, Chengguan District, Lanzhou City 730030, P. R. China
6. Department of Gastroenterology, Weinan Central Hospital, Middle section of Shengli Street, Linwei District, Weinan 714099, P. R. China
7. Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuanjiagang, Yuzhong District, Chongqing 400050, P. R. China
8. Department of Gastroenterology, Fuling Hospital Affiliated to Chongqing University, No. 2, Gaosuntang Road, Fuling District, Chongqing 408099, P. R. China
9. Department of Gastroenterology, The Second Affiliated Hospital of Baotou Medical College, No. 30, Hude Mulin Street, Qingshan District, Baotou City 014010 P. R. China
10. Department of Gastroenterology, Longgang District People’s Hospital, No. 53, Aixin Road, Central City, Longgang District Shenzhen 518172, P. R. China
11. Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Luzhou 646099, P. R. China
12. Department of Gastroenterology, The Second Affiliated Hospital Chongqing Medical University, 76 Linjiang Road, Yuzhong District, Chongqing 400010, P. R. China
13. Department of Gastroenterology, The First Affiliated Hospital of Chendu Medical College, No. 278, Middle Section of Baoguang Avenue, Xindu District, Chengdu 610500, P. R. China
14. Department of Gastroenterology, The First Affiliated Hospital of Kunming Medical University, No. 295, Xichang Road, Wuhua District, Kunming 650000, P. R. China
15. Yunnan Province Clinical Research Center for Digestive Diseases, No. 295, Xichang Road, Wuhua District, Kunming 650000, P. R. China
16. Department of endoscopy, Sun Yat-sen University Cancer Center, 651 Dongfeng East Road, Yuexiu District, Guangzhou 510060, P. R. China
17. Department of Gastroenterology, The Fifth Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, P. R. China
18. Department of Gastroenterology, Haikou People’s Hospital, 43 Renmin Avenue, Haikou 570208, P. R. China
19. Department of Gastroenterology, People’s Hospital of Xinjiang Autonomous Region, 91 Tianchi Road, Urumqi 830000, P. R. China
20. Department of Gastroenterology, Suining Central Hospital, No. 127, Desheng West Road, Chuanshan District, Suining 629099, P. R. China
21. Department of Endoscopy Center, The First Affiliated Hospital of Sun Yat-sen University, No. 58, Zhongshan 2nd Road, Guangzhou Guangzhou 510080, P. R. China