Abstract: Objective To investigate a possible correlation between C677T polymorphism in the methylenetetrahydrofolate reductase （MTHFR） gene and chemotherapy efficacy in patients with pulmonary adenocarcinoma. Methods Peripheral blood samples from 92 patients with pulmonary adenocarcinoma were collected before chemotherapy，and the C677T polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism（PCR-RFLP）.We examined whether genotype correlated with whether the patients showed partial response（PR）， stable disease（SD） or progressive disease（PD） following chemotherapy. Results Of the 92 patients，56 （60.9%） had wild-type genotype （CC），13（14.1%） were homozygous mutant（TT），and 23（25.0%） were heterozygous mutant （CT）.Among the patients treated with pemetrexed/carpoplatin as first-line regimen，CC patients showed an overall response rate（ORR）of 35.7%， with 20 CC patients achieving PR；19，SD；and 17，PD.Among TT patients，ORR was 15.4%，with 2 patients achieving PR；7，SD； and 4，PD.Among CT patients，ORR was 0，with 13 achieving SD and 10，PD.ORR was significantly higher in CC patients than in TT or CT patients（P=0.001）.In addition，CC patients showed significantly longer time to progression（6.2 months） than did TT or CT patients（4.7 months；P=0.023）.Among the patients treated with gemcitabine/nedaplatin or docetaxel/nedaplatin as second-line regimen，2 CC patients showed PR；5，SD；and 10，PD.3 TT patients achieved SD；among CT patients， 1 achieved PR，2 SD and 7，PD.ORR was similar between CC and TT/CT patients（P=1.000）. Conclusions Pemetrexed in combination with carboplatin may be associated with greater therapeutic efficacy and longer time to progression in CC patients than in TT/CT patients.However， genotype at the MTHFR C677T polymorphism does not appear to influence the therapeutic efficacy of gemcitabine/nedaplatin or docetaxel/nedaplatin.

Key words: Lung neoplasms, Non-small cell lung cancer, Methylenetetrahydrofolate reductase, Gene polymorphism, Chemotherapy