ALDH18A1 and bladder transitional cell carcinoma: We found that missense mutations were the most frequent mutation type in BLCA, with a lower mutation rate in the GPR-high + TME-low group (93.04%) than in the GPR-low + TME-high group (95.61%), and further calculated the TMB of each risk group and found that the GPR-high + TME-low group had a lower TMB than the GPR-low + TME-high group (95.61%).