To date, the most extensively studied poxvirus cancer gene therapies have used vectors encoding the cell surface costimulatory molecules B7-1 (CD80), ICAM-1 (CD54), and LFA-3 (human CD58; murine CD48) termed collectively as TRICOM and the soluble enhancer of antigen-presenting dendritic cells/pathways GM-CSF. Here, CD80 is linked to cancer.