Does the hpv virus cause anal cancer?

Yes: Yes, hpv directly causes at least 50% of all vaginal and vulvar cancers, as well as all cerivical cancers, much of anal cancers, 70% of head-and-neck cancers and most non-melanoma skin cancers amongst other problems! that's a ton of cancers from one virus!

It can: Hpv is associated with genital warts and cancers as well as head and neck cancers and linings. This does not mean everyone who has these cancers has hpv also. Therefore hpv is associated with and increases the risk of getting these cancers including anal cancers. Hpv is sexually transmitted and there is a vaccine to help prevent it.

Yes: Yes, I have a half dozen HIV positive gay males that developed anal cancer due to the hpv. It begins as an intraepithelial lesion morphology change.