In vitro, the RT112 bladder cancer cell line was derived from a human bladder tumor and expresses the FGFR3‐TACC3 fusion protein, while the UMUC‐14 cell line expresses an endogenous activated mutant form of FGFR3 (FGFR3‐S249C).33, 44. The gene discussed is FGFR3; the disease is urinary bladder carcinoma.