1. Department of Pathology; Hospital of Gynecology and Pediatrics 3A, Instituto Mexicano del Seguro Social, Delegación Norte; Mexico, DF; Mexico
2. Medical Oncology Research Unit; Oncology Hospital, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social; Mexico, DF; Mexico
3. National Cancer Institute; Secretaria de Salud; Mexico, DF; Mexico