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Human papillomavirus hpv causes a variety of anogenital cancers and is considered the primary cause of anal canal cancer 1 , 2. Other than cervical cancer, anal cancer was expected to be the most commonly diagnosed anogenital hpv -associated cancer in 3. Although anal cancer is less common than cervical cancer, its incidence in U. During the same period, the incidence of cervical cancer in women decreased 4. An increasing incidence of anal cancer noted also in Europe 5 is likely attributable to increased anal disease occurring in immunocompromised people and in men who have sex with men msm 6 β 8.
Indeed, the risk ratio of observed to expected anal cancers has been reported to be Appropriately, anal cancer research to date has focused on these populations.
Epidemiologic research also indicates that heterosexual men with hiv , even in the absence of receptive anal intercourse, may have a high prevalence of precancerous anal lesions associated with hpv Finally, a clearer understanding of the risks associated with anal hpv in heterosexual men may provide important contrasts that will help clarify the picture of anal hpv -related morbidity and mortality in other populations.
As in cervical cancer, most anal cancers are associated with oncogenic hpv types 16 and 18 2 , Given an identical pathogen and similarity of the tissue including a transformation zone in the anal canal that is bounded on each side by squamous and columnar epithelium 12 , hpv -induced carcinogenesis leading to cervical cancer is comparable to the process that leads to anal canal cancer.
