The transmembrane mutations Y375C and C382Y, plus the extracellular domain mutations S252W, W290C and P253R are more frequent than the kinase domain mutations N549H/K and K659E, according to Helsten et al.96 The most frequent SNVs in FGFR3 are R248C and S249C in the extracellular domain and G370C and Y373C in the transmembrane domain, with reports in urothelial carcinomas.104,105 Last, but not least, SNVs in FGDR4 are notable in rhabdomyosarcoma, with V550E and N535K contributing to autophosphorylation of the receptor, while Y367C was identified in MDA-MB453 BC cell line.106,107. The gene discussed is FGFR3; the disease is urothelial carcinoma.