However, in stage T1 tumors and MIBC, FGFR3 mutations are less common and account for only 10% to 20% in tumors of stage T2 or above.13 A prior 2007 study by Tomlinson et al14 implicated FGFR3 in contributing to the risk of bladder cancer development. The gene discussed is FGFR3; the disease is urinary bladder cancer.