(UroToday.com) Molecular characterization of bladder cancer by gene expression profiling has generated disease subtypes that are associated with response to neoadjuvant therapy in muscle-invasive bladder cancer. Post-treatment residual disease appears to undergo changes in molecular profile, characterized recently by a publication1 into four expression profile clusters: CC1 (basal), CC2 (Luminal), CC3 (Immune) and CC4 (Scar-like). These profiles (postNAC) were generated from residual disease in patients treated with platinum chemotherapy. In this poster presentation, the authors endeavored to create a molecular characterization system for residual bladder cancer after pembrolizumab therapy.