1. Department Obstetrics and Gynecology, Hospital of Leon, Leon, Spain

2. Department of Mathematics, University of Leon, Leon, Spain

3. Department of Pathology, Hospital of Leon, Leon, Spain

4. Department Obstetrics and Gynecology, Hospital Universitario Gregorio Marañón, Madrid, Spain

5. Department of Gynecologic Oncology, Hospital Puerta de Hierro, Madrid, Spain