Anal SCC is very similar histologically to cervical cancer, and precancerous lesions of the anus (AIN) and cervix (cervical intraepithelial neoplasia [CIN]) are graded similarly (normal, low-grade [AIN- or CIN-1], high-grade [AIN- or CIN-2 or 3], SCC). Rates of progression of high-grade dysplasia in HIV-infected MSM is around 15%, over mean follow-up periods of 2 and 5 years. In HIV-uninfected persons, anal cancer detection at an earlier stage improves survival. Thus, early cancer detection in HIV-infected patients may also be beneficial.