FGFR3 and urinary bladder cancer: Bladder carcinomas are classified as either superficial or invasive, with the two types of tumors characterized by different sets of genomic alterations.1,2 Although occasionally superficial tumors evolve to become invasive, the two types of bladder cancer represent distinct biological entities.1,2 It is interesting that although activating mutations in FGFR genes (primarily FGFR-3) are common in the superficial form of bladder cancer, overexpression of fibroblast growth factor 2 (FGF-2) is often observed in invasive bladder cancer.3–5