PT - JOURNAL ARTICLE AU - Khaleel I Al-Obaidy AU - Liang Cheng TI - Fibroblast growth factor receptor (<em>FGFR</em>) gene: pathogenesis and treatment implications in urothelial carcinoma of the bladder AID - 10.1136/jclinpath-2020-207115 DP - 2021 Aug 01 TA - Journal of Clinical Pathology PG - 491--495 VI - 74 IP - 8 4099 - http://jcp.bmj.com/content/74/8/491.short 4100 - http://jcp.bmj.com/content/74/8/491.full SO - J Clin Pathol2021 Aug 01; 74 AB - Dysregulation of fibroblast growth factor receptors (FGFRs) has been implicated in several human malignancies, including urothelial carcinoma. In urothelial carcinoma, the oncogenic role of mutated FGFR is mediated by the RAS-mitogen-activated protein kinase pathway, resembling the effects observed with activated HRAS. Activating somatic mutations of FGFR3 are clustered in three hotspots in exons 7, 10 and 15, and are almost always missense mutations leading to amino acid substitution in the external, transmembrane or intracellular regions of the receptor. A fusion of FGFR3 to transforming acid coiled-coil containing protein 3, FGFR3 amplification and alternative splicing leading to aberrant FGFR3 activation are less common molecular alterations. In April 2020, the Food and Drug Administration (FDA) approved the first targeted FGFR therapy, erdafitinib, in patients with locally advanced or metastatic bladder cancer who have progressed on platinum-based chemotherapy. Herein, we reviewed the normal structure and function of FGFR. We also explored its role in the development of urothelial carcinoma and major developments in the FGFR-targeted therapy.