Eighty percent of HIV-positive and 50 percent of HIV-negative women in a recent study had anal HPV infections (human papillomavirus, which causes cervical and anal cancers). The study, reported in the journal AIDS in January, included 470 positive and 185 negative women. Half had never had anal sex: HPV can migrate from the cervix or vagina.

HPV caused many more anal lesions in the positive women than in their negative peers. Such lesions may become cancerous, so although the study doesn't include recommendations, positive women might want to ask their doctors to screen them with anal Pap smears or anoscopy. (Get more information at poz.com.)

Meanwhile, the Gardasil vaccination, already approved for girls and young women up to age 26, may soon be available for boys and men and for women from 27 to 45. Gardasil protects against some cancer-causing HPV strains in people who haven't yet contracted those strains.