Urothelial cancer is not the only cancer type that harbors FGFR alterations, which may be found in breast cancer, non–small cell lung cancer, colorectal cancer, and endometrial cancer, among others.4 The availability of a drug targeting FGFR2 and FGFR3 alterations for 1 tumor type (ie, urothelial cancer) may encourage the off-label use in other types of cancers with these alterations. Here, FGFR3 is linked to breast carcinoma.