Many human viruses by direct or indirect mechanisms, contribute to the development of cancer. Historically, these studies focused on viruses that were present in tumor cells, Epstein Barr Virus (EBV) for example, but did not consider indirect mechanisms that would explain many other relationships between infectious disease and cancer. With the burgeoning HIV epidemic, immuno-suppressed HIV+ individuals have poor control over infection and replication of well-known tumor viruses. Cancers associated with these viruses increased dramatically, including Kaposi’s sarcoma caused by Human Herpes Virus-8 (HHV-8), B cell lymphoma associated with EBV, or anogenital cancer caused by Human Papillomavirus (HPV). In the United States and Europe, cancer is the leading cause of death for individuals with HIV disease, due to aging of the infected population, durable impacts on the host capacity for tumor surveillance and additional infectious agents that are affected directly or indirectly by HIV. Our program on Cancer Viruses integrates clinical and basic research on virus-associated cancers. We are developing multidisciplinary approaches to study HIV+ patients with cancer, in addition to the work on a preventive HIV vaccine (DeVico, Lewis, Gallo) that would reduce cancer incidence. Gallo’s group studies the potential for opportunistic microbial pathogens, including unique mycoplasma species, to promote lymphoma in the context of HIV disease. Popovic and Garzino-Demo are collaborating with Dr. Martin Edelman (Greenebaum Cancer Center) on a possible viral etiology for lung cancer in “never-smokers.” Garzino-Demo is revisiting the mechanisms for increased lymphoma in HIV disease and Gartner studies novel stem-like cells that may help to explain the rising rates of Hodgkin’s lymphoma in people with HIV disease. Lu investigates human defensins and their capacity to prevent HPV infection that may be related to the rising rates for anogenital cancer in HIV disease. J.S. Gao will join the IHV to continue work on the HHV-8 tumor virus responsible for Kaposi’s sarcoma (KS), including collaborative studies with Redfield and Blattner, to understand unusual regional variation within Africa and why that affects the rates for HIV-associated KS. The program on Cancer Viruses is an area of opportunity within IHV and builds on the traditional strengths and research interests of Dr. Gallo.