HPV cervical infection. Light micrograph of a cervical smear revealing epithelial cells infected with the human papilloma virus (HPV). HPV causes genital warts & is implicated in the development of cervical cancer. Typical changes to the blue & pink-stained squamous cells include binucleation (seen at left) and formation of large haloes around the nuclei (koilocytosis). Cervical cancer is thought to be caused by a continuation of such cellular changes. In this patient, the smear would be considered borderline abnormal" and repeated after three months. Haematoxylin & eosin stain. Magnification: x200 at 35mm size."