PDCD1 and bladder transitional cell carcinoma: In the end, we proved that the expression of PMEPA1 was mutually associated with several immune checkpoints, including PD-1 (PDCD1), PD-L1 (CD274), CTLA-4, HAVCR2 (TIM-3), PDCD1LG2, TIGIT and LAG-3 in BLCA (Figure 3E and Table S11).