FGFR1 and lung carcinoma: First, the expression of both FGF2 and FGFR1 was markedly elevated in the pemetrexed-resistant lung cancer sublines derived from two different lung cancer cell lines originated from adenocarcinoma, whereas the inhibition of the FGF2-FGFR1 pathway using FGF2-targeting siRNA or the specific FGFR inhibitor PD173074 partially restored the pemetrexed sensitivity.