The fibroblast growth factor receptor type 1 gene (FGFR1) encodes one member of the FGFR tyrosine kinase (TK) family, which includes four kinases: FGFR1, 2, 3, and 4 (Figure 1). FGFR TKs play crucial roles in development and have been shown in cancers to be deregulated by either amplification, point mutation, or translocation (Turner and Grose 2010). Amplification or activation of FGFR1 has been reported in many cancers including oral squamous cell carcinoma (Freier et al. 2007), breast cancer (Turner et al. 2010), esophageal squamous cell carcinoma (Ishizuka et al. 2002), ovarian cancer (Gorringe et al. 2007), bladder cancer (Simon et al. 2001), prostate cancer (Edwards et al. 2003), and lung cancer, predominantly in the squamous subtype (Dutt et al. 2011; Weir et al. 2007; Weiss et al. 2010).
Figure 1. Schematic of FGFR signaling pathway. Growth factor binding to FGFR results in activation of the MAPK signaling pathway (RAS-RAF-MEK-ERK). The letter "K" within the schema denotes the tyrosine kinase domain.