1. Cancer Center, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
2. Department of Oncology, The Central Hospital of Jiangjin, Chongqing 402260, P.R. China
3. Department of Pathology, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China