1. Department of General Surgery, The Affiliated Zhengzhou Central Hospital of Zhengzhou University, Zhengzhou, Henan 450007, P.R. China
2. Department of Experimental Oncology and Animal Center, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
3. Department of Surgery, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China