1. Department of Obstetrics and Gynaecology; Hokkaido University School of Medicine; Sapporo Japan
2. Division of Gynecologic Oncology; National Hospital Organization, Hokkaido Cancer Center; Sapporo Japan
3. Division of Pathology; National Hospital Organization, Hokkaido Cancer Center; Sapporo Japan
4. Department of Surgical Pathology; Sapporo Medical University School of Medicine; Sapporo Japan