1. Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
2. Division of Molecular Modification and Cancer Biology, National Cancer Center Research Institute, Tokyo 104-0045, Japan
3. Department of Pathology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
4. Department of Pathology, Faculty of Medicine, Akita University, Akita 010-8543, Japan
5. Center for Female Preventive Medicine, Kanagawa Health Service Association, Naka-ku, Yokohama, Kanagawa 231-0021, Japan