By studying the effects of FGFR3 mutations using OH‐BBN‐induced, genetically engineered mouse models of invasive bladder cancer, we report three significant findings: firstly, in the presence of mutationally activated FGFR3 S249C, there was an increased number of mice that developed bladder tumours and the tumour phenotype was more advanced (Figure 2). This evidence concerns the gene FGFR3 and urinary bladder neoplasm.