A folylpoly-γ-glutamate synthase single nucleotide polymorphism associated with response to pemetrexed treatment combined with platinum for non-small cell lung cancer.

Objectives: In this study, we investigated whether single nucleotide polymorphisms (SNPs) in folylpoly-γ-glutamate synthase (FPGS), which catalyzes the polyglutamation of pemetrexed (PEM), is related to FPGS expression and the response to PEM in non-small cell lung cancer (NSCLC).
Materials and Methods: We first examined FPGS protein expressions according to FPGS SNPs genotype groups in 15 lung adenocarcinoma cell lines. Next, 101 non-squamous NSCLC patients treated with PEM and platinum drugs were classified into FPGS SNP genotype groups to investigate the relation between FPGS SNP genotypes and treatment outcome.
Results: When the 15 adenocarcinoma cell lines were classified into FPGS SNP 2572C>T genotype groups, we found that the FPGS protein expression was significantly higher in the CC genotype group than in the TT+CT genotype group (p=0.0022). In contrast, there was no significant difference in FPGS expression when another FPGS SNP was analyzed. We also examined the FPGS SNP 2572C>T genotype in 101 non-squamous NSCLC patients treated with PEM and platinum drugs. Among these 101 patients, response rate was significantly higher in the CC genotype group than in the TT+CT genotype group (p=0.0034). When we examined the patients treated with PEM, platinum drugs and Bev, almost all (29/33) were classified into the TT+CT genotype group. The response rate, progression-free survival, and over-all survival were all significantly better in the patients of the TT+CT genotype group who also received Bev than in those who did not receive Bev (p=0.034, 0.021, 0.018, respectively).
Conclusion: FPGS SNP 2572C>T is a predictive marker of the efficacy of PEM and platinum drugs for NSCLC.
(Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)