In 2004, the investigators initiated the Toronto Research for Anal Cancer Evaluation (TRACE) study to evaluate the performance characteristics of anal cytology and anal HPV testing for the detection of anal cancer precursors in 401 HIV-infected MSM. Overall, the information gleaned from this large cohort demonstrated that the burden of HPV disease was high in HIV-positive MSM, but that anal Pap smears are too insensitive a tool to rely on for diagnosis. Due to the poor test performance of anal cytology as a single, primary screening test, its use has not resulted in widespread uptake for screening. Exploration of the potential benefit and utility of other screening tests such as HPV-DNA testing, perhaps in conjunction with anal cytology, is needed.