In vitro experiments, including proliferation and migration assays, were performed in T24 and 5637 bladder cancer cells following MAOA knockdown.<h4>Results</h4>BLCA samples were classified into two subtypes (C1 and C2), with C1 showing better overall survival, enhanced steroid metabolism, downregulated chemokine signaling, and lower immune scores. Here, MAOA is linked to bladder transitional cell carcinoma.