Archive | 2019
HPV Infection and Gynecological Cancers
Abstract
Human papilloma viruses (HPVs) are sexually transmitted, double-stranded oncogenic DNA viruses. HPV infections account for approximately 5% of all malignancies worldwide. Almost all cervical carcinomas (squamous cell carcinoma and adenocarcinoma) and a significant proportion of other anogenital carcinomas (vulvovaginal, anal, penile carcinomas) and oropharyngeal carcinomas are attributed to HPV infections. The common high-risk types seen in preinvasive and invasive lesions of the cervix are HPV 16 and HPV 18. The other common HPV types are HPV 6 and HPV 11, which belong to the low-risk category and are associated with genital warts. Most HPV infections are cleared within 6–12 months by the cell-mediated host immune response. A small proportion of infections that persist can develop into preinvasive lesions, which have a risk of progression to malignancy. The cofactors for persistence and progression of infection are smoking, parity, hormonal influences, other infections like HIV, etc. E6 and E7 proteins inhibit p53 and RB tumor suppressor genes, respectively, and are responsible for viral oncogenicity in the high-risk HPV types. Primary prevention by vaccination and screening by cytology and HPV DNA testing are available.