1. Cancer Center, Daping Hospital and Research Institute of Surgery, Third Military Medical University, Chongqing 400042, P.R. China
2. Department of Oncology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P. R. China
3. Department of Oncology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P. R. China
4. Department of Gynecology, People' s Hospital of Xinjiang Uyhgur Autonomous Region, Urumqi, Xinjiang 830001, P. R. China