Prevalence and persistence of HPV-16 molecular variants in the anal canal of men: The HIM study.

Background: HPV-16 causes approximately 90% of anal canal (AC) cancers worldwide. This study aimed to evaluate the prevalence and persistence of HPV-16 genetic variants in the AC of men from three different countries (Brazil, Mexico and United States) and to further identify sociodemographic and behavioral factors associated with these infections.

Methods: Participants from the multinational prospective HPV Infection in Men (HIM) Study who had at least one HPV-16 positive AC swab were included. Characterization into HPV-16 genetic variants was successfully performed by PCR-sequencing in 95.6% (217/227) samples and these were classified into HPV-16 lineages and sublineages.

Results: We observed higher prevalence of lineage A variants, mainly from A1 sublineage, in all countries. Non-A lineage variants were mostly detected in men from Brazil, where higher diversity of sublineage variants was detected during follow-up. Compare to men detected with Non-A HPV-16 lineage variants, men infected with lineage A reported a higher lifetime number of female sexual partners. Finally, a significantly higher prevalence of Non-A lineage variants was observed among men who have sex with men (MSM) with a transient HPV-16 AC infection (p = 0.033), but no significant differences regarding variants lineages and persistence status were observed when stratified by country, self-reported ethnicity or age.

Conclusions: Our data extend previous reports which indicate that globally HPV-16 variants are unevenly distributed, and contribute further to studies of the natural history of AC HPV infections in men.