PDCD1 and urinary bladder cancer: In bladder cancer tissue elevated expression of immune checkpoint antigens such as programmed cell death protein-1 (PD-1; =CD279), its ligand, PD-L1 (=CD274), anti-cytotoxic T-lymphocyte associated antigen-4 (CTLA-4, =CD152), and B7-H3 (=CD276) was observed [7,8,9].