Single nucleotide polymorphisms in XRCC1 and clinical response to platin-based chemotherapy in advanced non-small cell lung cancer

BACKGROUND & OBJECTIVE: DNA repair capacity correlated with sensitivity of cancer cells towards platin-based chemotherapy. This study examined the association between genetic polymorphisms of DNA repair gene XRCC1 and response to cisplatin- or carboplatin-based chemotherapy of advanced non-small cell lung cancer (NSCLC). METHODS: Totally 105 patients with advanced NSCLC were routinely treated with cisplatin- or carboplatin-based chemotherapy, and clinical response was evaluated after 2 to 3 cycles. XRCC1 genotypes were determined by PCR-RFLP methods using DNA samples isolated from peripheral blood collected before treatment. The odds ratios (ORs) and 95% confidence intervals (CIs) were computed by logistic regression. RESULTS: The response rate to the chemotherapy in patients with the 194Arg/Trp or Trp/Trp genotype significantly higher than that in patients with the Arg/Arg genotype (43.1% vs. 20.3%;OR=2.97,95% CI=1.15-7.72;P< 0.05). The response rate to chemotherapy was also significantly higher in patients with the 399Arg/Arg genotype than that in patient with the Arg/Gln or Gln/Gln genotype (41.5% vs. 21.2%;OR=2.65,95% CI=1.03-6.87;P< 0.05).Furthermore, it appeared that 194Arg/Trp and 399Arg/Arg genotypes had synergic effect on the chemotherapy efficacy. Patients with both of these two polymorphisms had a response rate of 66.7% which was significantly greater than that in patients with other genotypes (response rate ranging from 20.0% to 23.1%, P< 0.001). CONCLUSION: Polymorphisms in the XRCC1 gene may have significant impact on the response of NSCLC patients to platin-based chemotherapy.