FGFR3 and urinary bladder carcinoma: We also showed that MYC upregulated FGFR3 expression directly, by binding to enhancers upstream from FGFR3, as part of a FGFR3/MYC positive feedback loop operating both in vitro and in vivo in bladder cancer‐derived cell lines xenografts and in a PDX model bearing an FGFR3 mutation.