1 Department of Hepatobiliary Pancreatic Surgery, Changhai Hospital, Navy Military Medical University (Second Military Medical University), Shanghai, China.
2 Department of General Surgery, Naval Medical Centre of People's Liberation Army, Shanghai, China.
3 Department of Hepatobiliary Surgery, First People's Hospital of Jining, Jining, China.
4 Department of Pathology, Changhai Hospital, Naval Military Medical University (Second Military Medical University), Shanghai, China.