1. Department of General Surgery, Weihai Wendeng People's Hospital, Weihai, Shandong 264400, P.R. China
2. Department of Clinical Laboratories, Weihai Central Hospital, Weihai, Shandong 264400, P.R. China
3. Department of Breast Surgery, Weihai Central Hospital, Weihai, Shandong 264400, P.R. China