Yi-Xin Lin1, Zi-Ming Liu1, Yi-Yun Fu2, Qian-Bin Jia3. 1. Department of Bile Duct Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China. 2. Department of Pathology, West China Hospital, Sichuan University, Chengdu, Sichuan, China. 3. Department of Bile Duct Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China. Electronic address: qianbinjia@126.com.