Genetic Polymorphism of XRCC1 Correlated with Response to Oxaliplatin-Based Chemotherapy in Advanced Colorectal Cancer

To examine the association between genetic polymorphisms of XRCC1 Arg399Gln(G -> A) and response to oxaliplatin-based chemotherapy in advanced colorectal cancer. XRCC1 genotypes of totally 99 patients(37 stage III, 62 stage IV)with advanced colorectal cancer treated with oxaliplatin-based chemotherapy were detected by TaqMan-MGB probe allelic discrimination method. And clinical response of 62 patients in stage IVafter 2 to 3 cycles of chemotherapy were evaluated. Also time to progress (TTP) of all patients were evaluated. Of the genotype frequencies in all patients, up to 52.53 % were G/G genotype, 9.09 % were A/A genotype, and 38.38 % were G/A genotype. The response rate (CR+PR) of 62 patients in stage IV was 61.29 % (19/31). Patients with G/G genotype showed enhanced respond to chemotherapy compared to those with G/A+A/A (x (2) = 5.6, P = 0.029; OR = 3.845, 95 %CI = 1.231 similar to 12.01, P = 0.018). Individuals with the G/G genotype had a TTP of 10.0 (8.88-11.12) months, those with the G/A+A/A genotype had an TTP of 5.0(4.26-5.74) months. The log-rank test was marginally significant (x (2) = 29.20, P < 0.01). The Cox proportional hazards model, adjusted for stage, performance status, and chemotherapy regimen, showed that only XRCC1 G/G genotypes increases the OR significantly (OR = 3.555; 95 % CI, 2.119 similar to 5.963; P < 0.01). The results suggest that XRCC1 Arg399Gln polymorphisms is associated with the response to oxaliplantin-based chemotherapy and time to progression in advanced colorectal cancer in Chinese population. It is proposed that the XRCC1 Arg399Gln polymorphism should be routinely detected to screen patients who are more likely benefit from oxaliplantin-based treatment.