Associations of Polymorphisms in DNA Repair Genes and MDR1 Gene with Chemotherapy Response and Survival of Non-Small Cell Lung Cancer

<div><p>Objectives</p><p>We aimed to determine the associations of genetic polymorphisms of excision repair cross-complementation group 1 (<i>ERCC1</i>) rs11615, xeroderma pigmentosum group D (<i>XPD</i>/<i>ERCC2)</i> rs13181, X-ray repair cross complementing group 1 (<i>XRCC1</i>) rs25487, <i>XRCC3</i> rs1799794, and breast cancer susceptibility gene 1 (<i>BRCA1</i>) rs1799966 from the DNA repair pathway and multiple drug resistance 1 (<i>MDR1/ABCB1</i>) rs1045642 with response to chemotherapy and survival of non-small cell lung cancer (NSCLC) in a Chinese population.</p><p>Materials and Methods</p><p>A total of 352 NSCLC patients were enrolled to evaluate the associations of the six SNPs with response to chemotherapy and overall survival. Logistic regressions were applied to test the associations of genetic polymorphisms with response to chemotherapy in 161 advanced NSCLC patients. Overall survival was analyzed in 161 advanced and 156 early stage NSCLC patients using the Kaplan-Meier method with log-rank test, respectively. Multivariate Cox proportional hazards model was performed to determine the factors independently associated with NSCLC prognosis.</p><p>Results</p><p><i>BRCA1</i> rs1799966 minor allele C (TC+CC <i>vs.</i> TT, OR = 0.402, 95%CI = 0.204−0.794, p = 0.008) and <i>MDR1/ABCB1</i> rs1045642 minor allele A (GA +AA <i>vs.</i> GG, OR = 0.478, 95%CI = 0.244−0.934, p = 0.030) were associated with a better response to chemotherapy in advanced NSCLC patients. Survival analyses indicated that <i>BRCA1</i> rs1799966 TC+CC genotypes were associated with a decreased risk of death (HR = 0.617, 95% CI = 0.402−0.948, p = 0.028) in advanced NSCLC patients, and the association was still significant after the adjustment for covariates. Multivariate Cox regression analysis showed that <i>ERCC1</i> rs11615 AA genotype (<i>P</i> = 0.020) and smoking (p = 0.037) were associated with increased risks of death in early stage NSCLC patients after surgery.</p><p>Conclusions</p><p>Polymorphisms of genes in DNA repair pathway and <i>MDR1</i> could contribute to chemotherapy response and survival of patients with NSCLC.</p>