1. Teaching and Research Section of Surgery, Xiangnan University Affiliated Hospital, Chenzhou, Hunan 423000, P.R. China
2. Department of Internal Medicine, Xiangnan University Affiliated Hospital, Chenzhou, Hunan 423000, P.R. China
3. Department of Oncology, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P.R. China