1. Department of General Surgery, Peking University First Hospital, Beijing 100034, P.R. China
2. Central Laboratory, The Fifth Central Hospital of Tianjin, Tianjin 300450, P.R. China
3. Department of Pathology, The Fifth Central Hospital of Tianjin, Tianjin 300450, P.R. China
4. Department of Pathology, Tianjin Central Hospital of Gynecology and Obstetrics, Tianjin 300100, P.R. China
5. Department of Orthopedics, Peking University People's Hospital, Beijing 100044, P.R. China