NCI investigators are collaborating with Italian colleagues on a population-based case-control study of non-HIV associated classical Kaposi sarcoma (cKS) in Italy to better characterize risk factors for cKS among Kaposi sarcoma-associated herpesvirus (KSHV) seropositive individuals. Results from the study of over 1,200 individuals confirmed a previous observation that cigarette smoking is associated with a decreased risk of cKS. Analyses from this study also revealed possible associations for diabetes and corticosteroid use, findings that require replication but are biologically plausible given that KS development is affected by modulation of immune responses and that diabetes and corticosteroid use are associated with inflammatory states and immunosuppression.