FGFR1 and cancer: FGFR1 protein expression by IHC revealed a similar pattern of overlapping expression levels between the amplified and non-amplified tumour samples, although while FGFR1 protein was undetectable in 68% (30/44) of the non-amplified tumours this was the case for only 9% of the amplified cancers (1/11) (S4B Fig).