Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) is the one EBV antigen that is expressed in all EBV associated malignancies. It has long been thought to go undetected by the cell mediated immune system. However, recent studies show that EBNA1 can be presented to both CD4+ and CD8+ T cells, making it a potential new target for immunotherapy of EBV related cancers.