Four different FGFRs (FGFR1, FGFR 2, FGFR3 and FGFR4) have been characterised and are well known for their importance in neuronal development and neural stem-cell maintenance.61,62 They are activated by the FGF family, which is the largest family of growth factor ligands, comprising 22 ligands in humans.63FGFR amplification is found in only 3.2% of glioblastoma cases,32 and is therefore, less common than PDGFRA amplification. The gene discussed is PDGFRA; the disease is glioblastoma.