Role of EGFR SNPs in survival of advanced lung adenocarcinoma patients treated with Gefitinib

Abstract

Aim: As a novel molecularly targeting agent for non-small-cell lung cancer (NSCLC), Gefitinib can block its tyrosine kinase activity of the epidermal growth factor receptor (EGFR). Genetic variations in EGFR may affect its protein function or expression and lead to diverse outcomes in NSCLC patients after Gefitinib therapy. Therefore, this prospective study examined whether EGFR single nucleotide polymorphisms (SNPs) are associated with different survival time in advanced lung adenocarcinoma patients treated with Gefitinib.

Methods: One hundred and twenty-eight patients with stage IIIB or IV lung adenocarcinoma receiving Gefitinib target therapy between 2008 and 2010 were recruited in this study. Six EGFR haplotype-tagging SNPs were genotyped by the Sequenom MassArray system. Survival by different genotypes was compared using Kaplan-Meier methods. Cox proportional hazards models were applied to estimate the effect of prognostic factors on overall survival (OS) and progression-free survival (PFS).

Results: After the median 16.6 months of follow-up, the unfavorable EGFR rs2293347AA or GA genotype was significantly correlated with shorter OS (AA vs. GG: 2.0 vs. 21.0 months; hazard ratio (HR)=2.44, 95% confidence interval (CI)=1.06-5.56; P=0.036; GA vs. GG: 15.0 vs. 21.0 months; HR=1.75, 95%CI=1.08-2.86, P=0.025) compared with the favorable rs2293347GG genotype. The prognostic significance of EGFR rs4947492 polymorphism on OS also existed (GG carriers vs. AA carriers: median OS=24.6 vs. 14.9 months, HR=0.29, 95%CI=0.10-0.83, P=0.021). No significant associations were found among other EGFR SNPs and survival.

Conclusion: EGFR rs2293347 and rs4947492 SNPs might be potential predictive markers of OS in advanced lung adenocarcinoma patients treated with Gefitinib.