Abstract: OBJECTIVE: To investigate the relationship between single nucleotide polymorphisms of DNA repair genes ERCC1 C118T and XPD Lys751Gln and sensitivity to platinum_based chemotherapy in non_small_cell lung cancer(NSCLC). METHODS: A total of 73 patients with NSCLC were analyzed. All the patients were treated with platinum_based chemotherapy and the DNA of their peripheral blood was obtained before the therapy. ERCC1 and XPD genotypes were evaluated by DNA sequence and the polymerase chain reaction_restrictive fragment length polymorphism (PCR_RFLP) method. RESULTS: The clinical benefit rates to therapy among the patients with ERCC1 C118T C/C,C/T and T/T genotypes were 94.9％,71.4％and 83.3％, respectively . The clinical benefit rate of C/C genotype was significantly higher than C/T and T/T genotypes. There were significant differences in clinical benefit rates to platinum_based chemotherapy (P<0.05).The clinical benefit rates to therapy among the patients with XPD Lys751Gln Lys/Lys and Lys/Gln genotypes were 80.3％and 75.0％, respectively. There were no significant differences in clinical benefits to platinum_based chemotherapy(P=0.702).The XPD Gln/Gln genotype was not detected. There were no significant differences between the genetic polymorphisms and clinical benefits to platinum_based chemotherapy on ERCC1 C118T and XPD Lys751Gln(P=0.134 and P=0.236). CONCLUSION: Single nucleotide polymorphisms of ERCC1 C118T was associated with clinical response to platinum_based chemotherapy in NSCLC patients, suggesting the ERCC1 C118T SNP may be one of predictors for NSCLC patients who would be responsive to platinum agents.

Key words: ERCC1, XPD, non_small_cell lung carcinoma, single nucleotide polymorphisms, cisplatin