Yu Liu1,2, Dan Wang1,2, Zhao-Shen Li1,2, Liang-Hao Hu3,4. 1. Department of Gastroenterology, Gongli Hospital, The Second Military Medical University, 800 Xiangyin Road, Shanghai, China. 2. Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, 800 Xiangyin Road, Shanghai, China. 3. Department of Gastroenterology, Gongli Hospital, The Second Military Medical University, 800 Xiangyin Road, Shanghai, China. lianghao-hu@hotmail.com. 4. Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, 800 Xiangyin Road, Shanghai, China. lianghao-hu@hotmail.com.