1. Department of Oncology, Nanfang Hospital, Guangzhou, Guangdong 510515, P.R. China
2. Department of Orthopaedic Surgery, Nanfang Hospital, Guangzhou, Guangdong 510515, P.R. China
3. Department of General Surgery, Taixin Hospital, Dongguan, Guangdong 523000, P.R. China
4. Department of Gastroenterology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China