While many common genes were altered in BUC and UTUC, the respective prevalence differed, with a higher rate of alterations in UTUC than in BUC for FGFR3 (35.6% vs. 21.6%, p = 0.065), HRAS (13.6% vs. 1.0%, p = 0.001), and CDKN2B (15.3% vs. 3.9%, p = 0.016) and higher rates in BUC than in UTUC for TP53 and ARID1A. This evidence concerns the gene FGFR3 and renal pelvis/ureter urothelial carcinoma.