CD80 and neoplasm: Transducing tumors with the B7 ligands CD80 or CD86 can enhance anti-tumor immunity by enabling the tumor cells to directly deliver antigenic and costimulatory signals to T and NK cells (Townsend and Allison, 1993; Chen et al., 1992; Wilson et al., 1999; Galea-Lauri et al., 1999).