Targeted immune gene expression profiling of FGFR-altered bladder cancer reveals a distinct immunological landscape from FGFR wildtype tumor

Fibroblast growth factor receptor (FGFR) alterations are prevalent in bladder cancer and represent potential therapeutic targets. FGFR-altered tumors have been linked to immunologically “cold” tumor microenvironments and low PD-L1 expression, which have been associated with poorer outcomes with immunotherapy. Conflicting data exists on FGFR alterations and response to immunotherapy, possibly due to variations in PD-L1 expression, FGFR alteration heterogeneity, and changes in the tumor microenvironment. To further characterize the tumor immune microenvironment of FGFR-altered bladder cancer, this study assessed the immune gene expression profiles of bladder tumors harboring FGFR fusions, non-fusion FGFR mutations, and FGFR wildtype tumors.