Department of Gastroenterology and Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Fengtai District, Beijing, 100069, China. Department of Gastroenterology, Tianjin Third Central Hospital, Tianjin, China. Department of Hepatology, Beijing Ditan Hospital, Affiliated with Capital Medical University, Beijing, China. Department of Hepatology, PLA 302 Hospital, Beijing, China. Liver Diseases Center, Beijing Friendship Hospital, Affiliated with Capital Medical University, Beijing, China. Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany. Department of Gastroenterology and Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Fengtai District, Beijing, 100069, China. dinghuiguo@medmail.com.cn.