CD274 and cancer: Functionally, B7-H1 overexpressioncorrelates with worse prognosis and resistance to anti-cancer therapies (8, , –11).Mechanistically, B7-H1 binds to its receptor, programmed death 1 (PD-1, also known asCD279) on T cells, inducing T-cell apoptosis and thus protecting tumor cells from immuneattack (12).