1. Department of Gynecology and Obstetrics; People's Liberation Army (PLA) Medical School, Chinese PLA General Hospital; Beijing China
2. Department of Gynecology and Obstetrics; Beijing Chao-Yang Hospital; Beijing China
3. Department of Pathology; People's Liberation Army (PLA) Medical School, Chinese PLA General Hospital; Beijing China
4. Department of Gynecology and Obstetrics; The 306th Hospital of Chinese PLA; Beijing China