1. Department of General Surgery, 306 Hospital of PLA, Beijing 100101, P.R. China
2. Department of Hepatology, 302 Teaching Hospital of Peking University Health Science Center, Beijing 100101, P.R. China
3. Department of General Surgery, PLA 306 Clinical Hospital of Anhui Medical University, Beijing 230000, P.R. China
4. Department of Pathology, 306 Hospital of PLA, Beijing 100101, P.R. China