RB1 and renal pelvis/ureter urothelial carcinoma: Audenet and Sfakianos et al. reported that fibroblast growth factor receptor 3 (FGFR3) and HRAS were more significantly altered in UTUC, whereas TP53, RB1, and ERBB2 were more often altered in BUC, which supports the molecular differences between UTUC and BUC [4,5].