Approximately twenty percent of human cancer worldwide is associated with specific human viruses. The viruses include the papillomaviruses, hepatitis B virus, Epstein-Barr virus, and the human retroviruses. Despite the strong associations that have been made between these viruses and specific human tumors, major questions remain unanswered as to the role these viruses play in malignant progression. This meeting will examine the basic biology of these viruses and will examine general mechanisms of viral induced transformation and immortalization. In addition there will be sessions focused on the regulation of proliferation and differentiation of the target cells of these viruses which include hepatocytes, lymphocytes, and epithelial cells. New approaches to specific antiviral therapeutic strategies and to vaccine developments will be included. Session Topics: Viruses and Liver Cancer, Hepatotropic Viruses: Transcription and Replication, Epstein-Barr Virus, B Lymphocyte Proliferation and Biology, Human T-Leukemia Viruses, Human Immunodeficiency Viruses and Cancer, Targets of DNA Tumor Viruses 1: RB and its Partners, Targets of DNA Tumor Viruses 2: p53, Papillomaviruses and Cancer Progression, Papillomaviruses: Replication and Transcriptional Control, Epithelial Cell Proliferation and Differentiation Functions, Vaccine Strategies.