Ming-Yang Song1, Zhong-Hong Liu2, Li-Xia Zhao3, Bing-Rong Liu4. 1. Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; The Academy of Medical Science, Zhengzhou University, Zhengzhou, China. 2. Department of Gastroenterology, The Second Affiliated Hospital of Harbin Medical University, Heilongjiang, China. 3. Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; Department of Gastroenterology, The Second Affiliated Hospital of Harbin Medical University, Heilongjiang, China. 4. Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; Department of Gastroenterology, The Second Affiliated Hospital of Harbin Medical University, Heilongjiang, China. Electronic address: fccliubr@zzu.edu.cn.