In recent years, recurrent fusions of FGFR3 have been identified in a number of cancers, including glioblastoma and cancers of the lung and bladder, among others (Singh et al, 2012; Parker et al, 2013; Williams et al, 2013; Wu et al, 2013; Capelletti et al, 2014; Yuan et al, 2014; Wang et al, 2014; Carneiro et al, 2015; reviewed in Parker et al, 2014). The most common fusion partner of FGFR3 is TACC3 (transforming acidic coiled coil protein 3), a protein involved in mitotic spindle assembly and chromosome segregation (Lin et al, 2010; Burgess et al, 2015). FGFR3 fusions are constitutively active and may form oligomers in a ligand-independent manner based on dimerization domains provided by the fusion partner (Singh et al, 2012; Williams et al, 2013; Parker et al, 2013; reviewed in Parker et al, 2014). Transformation and proliferation appear to be promoted through activation of the ERK and AKT signaling pathways. In contrast, PLC gamma signaling is not stimulated downstream of FGFR3 fusions, as the PLC gamma docking site is not present in the fusion. FGFR3 fusions are sensitive to protein kinase inhibitors, suggesting their potential as therapeutic targets (Singh et al, 2012; Williams et al, 2013; Wu et al, 2013; reviewed in Parker et al, 2014).