Concluding overview: looking back, looking forward

The gamma -herpesviruses are a group of related agents which share tile sam e broad strategy for infection of and persistence within the lymphoid tissu es of their. hosts. Yet in evolutionary terms these agents are sufficiently diverse to display multiple different molecular mechanisms whereby that st rategy call be achieved. Attempts are made to relate the different in vitro growth transforming capacities of tile gamma (1)-herpesviruses, the T-lymp hotropic gamma (2)-herpesviruses and the B-lymphotropic gamma (2)-herpesvir uses to what is known about the biology of these virus infections in their natural or in experimental hosts. The review then summarizes the evidence l inking gamma -herpesviruses with oncogenesis and proposes that the diverse spectrum of Epstein-Barr virus and human herpesvirus 8-associated human tum ours falls into three pathogenically distinct categories. Many questions re main unanswered in the areas of gamma -herpesvirus biology and disease path ogenesis: resolving these questions will :require a broadening of our exper imental approaches and a willingness to relinquish 'single-model' panaceas.