1. Department of Obstetrics & Gynecology, School of Medicine, Keio University, Tokyo, Japan.
2. Department of Obstetrics & Gynecology, School of Medicine, Keio University, Tokyo, Japan
3. Department of Pathology, School of Medicine, Keio University, Tokyo, Japan
4. Oncogene Research Unit/Cancer Prevention Unit, Tochigi Cancer Center Research Institute, Tochigi, Japan