In addition to FGFR1β, other splice isoforms, including FGFR3ΔΑΒ, an FGFR3 isoform that lacks the IgI-IgII linker region, containing the acid box (AB), have been shown to alter heparin binding and FGF affinity and represent another mechanism of FGFR activation that may be exploited in cancer [110]. Here, VPREB1 is linked to cancer.