1 Department of Obstetrics and Gynecology, Key Laboratory for Gynecologic Oncology Gansu Province, the First Hospital of Lanzhou University, Lanzhou City, Gansu Province, 730000, PR China.
2 Department of Obstetrics and Gynecology, Key Laboratory for Gynecologic Oncology Gansu Province, the First Hospital of Lanzhou University, Lanzhou City, Gansu Province, 730000, PR China. eh0147@163.com.