1. Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
2. Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110005, P.R. China
3. Department of Surgery, Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
4. Department of Oncology, Liaoyang Central Hospital of China Medical University, Liaoyang, Liaoning 111010, P.R. China