FGFR4 and cancer: The FGF signalingsystem is highly relevant for the development, progression, and metastasisof many types of cancer.2 According toprevious analyses, the dysregulation of FGFRs has been detected in5–10% of human cancers,3 including7–23% FGFR1/2 overexpression in breast cancer,4 20% FGFR1 overexpression in nonsmall cell lung cancer,5 and 7–8% FGFR4 overexpression in rhabdomysarcoma.6 This indicates that the FGFR family is a promisingreceptor for targeting in cancer therapy.