( Helen Londe M.D. Contributing Editor ...)Testing for Human Papillomavirus,Health

Human papillomaviruses (HPVs) are small, closed circle, double-stranded DNA viruses, which are classified by nucleic acid sequence homology rather than serologic reactivity. Genital HPVs are the most prevalent sexually transmitted pathogens. Of the approximately 50 anogenital HPVs, there are a limited number of high and intermediate risk types detected in anogenital cancer biopsy specimens. Worldwide, HPV has been associated with 99.7% of squamous cell cancers of the cervix.

Most genital HPV infections in women produce transient squamous cell abnormalities of the cervix that are resolved completely, and the probability of any one HPV infection progressing to cervical cancer is quite small. Nevertheless, cervical cancer represents the second most common cancer in women, with 465,000 new cases and 200,000 deaths worldwide every year. Men infected with oncogenic HPVs are almost always clinically asymptomatic, and the risk for HPV-associated penile cancer is low. Anal HPV infection in men who have sex with men has a high risk for anal neoplasia, however, especially for those with HIV infections.

The recent promising results of the multi-country Gardasil vaccine Phase 3 clinical study showed that the vaccine, which targets HPVs 16 and 18, was 100% effective in preventing HPV 16/18-related moderate and high grade cervical intraepithelial neoplasia (CIN) and adenocarcinoma in situ. HPV 16 and 18 account for about 70% of cervical cancers. It is uncertain how long the vaccine is effective, although data suggest 5 to 10 years. Key questions regarding the vaccine target population and religious and cultural biases against giving a vaccine that prevents sexually transmitted disease to children need to be resolved. Although the public health success of HPV vaccination shows tremendous potential, oncogenic HPVs not included in the vaccine will continue to contribute to risk for development of CIN and cancer
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