The recent molecular classification of urothelial carcinoma divides it into two main pathogenetic pathways: low-grade noninvasive urothelial carcinoma, harboring mainly FGFR3 mutations that consequently affect FGFR3 expression, and high-grade invasive urothelial carcinoma, characterized by mutations in tumor suppressor genes like p53 and KDM6A that consequently affect their expression [37]. This evidence concerns the gene FGFR3 and urothelial carcinoma.