1. Department of Gynaecology, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, P.R. China
2. Department of Gynaecology and Obstetrics, Harbin Red Cross Central Hospital, Harbin, Heilongjiang, P.R. China
3. Department of General Surgery, Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, P.R. China