1. Department of Gastroenterology, The Second Hospital of Hebei Medical University, Hebei Key Laboratory of Gastroenterology, Hebei Medical University, Hebei Institute of Gastroenterology, Shijiazhuang, Hebei, China
2. Department of Pathology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
3. Department of Geriatric Medicine, Harrison International Peace Hospital, Hengshui, Hebei, China