Previous studies have shown that FGFR2/3 gene alterations, including FGFR3 activating mutations that affect either the extracellular (R248C and S249C) or transmembrane (G370C, S371C, Y373C, and G380R) domains of the protein, and gene fusions such as FGFR3-TACC3, are common in patients with urothelial carcinoma and cause constitutively activated FGF signaling, resulting in carcinogenesis4. The gene discussed is FGFR3; the disease is urothelial carcinoma.