DNA Repair Gene Polymorphisms Predict Favorable Clinical Outcome in Advanced Non-Small-Cell Lung Cancer

Background: Genetic polymorphisms of genes involved in DNA repair and glutathione metabolic pathways may affect patients' response to platinum-based chemotherapy. We retrospectively assessed whether single nucleotide polymorphisms (SNP) of DNA-repair genes ERCC1, XPD, XRCC1 and glutathione S-transferase genes GSTP1, GSTT1 and GSTM1 predict overall survival (OS), response and toxicity in 119 non-small-cell lung cancer (NSCLC) patients treated with platinum-based regimens as first- or second-line chemotherapy. Patients and Methods: Patients' genotypes were determined by PCR-RFLP and sequencing approaches. Results: ERCC1 (Asn118Asn) genotype was significantly associated with response to treatment. Patients with either one or two C alleles (C/C, C/T) at Asn118Asn were more likely to respond to platinum-based chemotherapy compared with those without the C allele (Odds ratio, 0.10; 95% CI, 0.013-0.828; P = .033, by binary logistic regression). There was a significant association between the ERCC1 C8092A polymorphism and OS (P = .009, by log-rank test), with median survival times of 9.8 (C/C) and 14.1 (C/A or A/A) months, respectively, suggesting that any copies of the A allele were associated with an improved outcome. Cox's multivariate analysis suggested that the joint effect of ERCC1 polymorphic variants (C8092A and N118N) (0 vs. 2, hazard ratio 2.5; 95% CI, 1.26-4.96; P = .009) as well as the XRCC1 N399Q polymorphism (AA vs. GA/GG, hazard ratio 3.1; 95% CI, 1.4-6.8; P = .005) were independent prognostic factors for OS in advanced NSCLC patients treated with platinum-based chemotherapy. Conclusion: These findings support the notion that assessment of genetic variations of ERCC2 and XRCC1 could facilitate therapeutic decisions for individualized therapy in advanced NSCLC.