1 Department of Gastroenterology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China.
2 Department of Pathology, Basic Medical College of North Sichuan Medical College, Nanchong, Sichuan, China.
3 Department of Pathology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China.
4 Department of Gastroenterology, West China Forth Hospital, West China School of Public Health, Non-communicable Diseases Research Center, West China-PUMC C. C. Chen Institute of Health, Sichuan University, Chengdu, China.