We used this bladder cancer specific RAS-BC assay together with similar assays that we developed previously for FGFR3 and PIK3CA[53], [55], to investigate the frequency of these mutations in an unselected series of primary tumors of 257 patients representing all stages and grades and 184 successive recurrent bladder tumors of 54 patients. The gene discussed is FGFR3; the disease is urinary bladder cancer.