CD274 and urinary bladder carcinoma: In addition, we performed key in vitro experiments and coculture assays using another bladder cancer cell line (TCCSUP, which is derived from anaplastic transitional cell carcinoma) to further confirm that the expression of PD-L1 was upregulated by glutamine deprivation through the EGFR/MEK/ERK/c-Jun pathway to impair T cell function.