1. Department of Pharmacology, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City 07360, Mexico
2. Service of Dysplasia, Gynecology and Obstetrics, ‘Dr Manuel Gea Gonz�lez’ Hospital General, Mexico City 14080, Mexico
3. Division of Anatomical Pathology, ‘Dr Manuel Gea Gonz�lez’ Hospital General, Mexico City 14080, Mexico
4. Service of Colposcopy, Instituto Nacional de Cancerolog�a, Mexico City 14080, Mexico
5. Medical Oncology, Instituto Nacional de Cancerolog�a, Mexico City 14080, Mexico
6. Service of Gynecology, Instituto Nacional de Cancerolog�a, Mexico City 14080, Mexico