B7-H1, a member of the B7 costimulatory molecule family, is expressed in many human cancers and B7-H1 facilitated antigen-specific T cell apoptosis in vitro or in mouse P815 tumor models was primarily mediated by one or more receptors other than the programmed cell death protein-1 (PD-1) (111). The gene discussed is PDCD1; the disease is cancer.