FGFR3 and urinary bladder cancer: Detecting FGFR3 hotspot mutations by Sanger sequencing for both grades of primary luminal non-invasive bladder cancer also demonstrated the prevalence of the gene mutation rate in codons 248 and 249 in low grade tumor cells (66.6% of samples had FGFR3 mutations), whereas this proportion was only 25% in high grade luminal NMIBCs (Figure A1).