ERCC1 and XPD/ERCC2 polymorphisms' predictive value of oxaliplatin-based chemotherapies in advanced colorectal cancer has an ethnic discrepancy: a meta-analysis

Our purpose is to evaluate the predictive value of the genetic polymorphisms of Excision repair cross-complementing group 1 (ERCC1) and xeroderma pigmentosum group D/excision repair cross-complementing group 2 (XPD/ERCC2) in patients with advanced colorectal cancer receiving oxaliplatin-based chemotherapy, and we performed a meta-analysis in order to obtain a more precise estimation for a more optimizing individual chemotherapy. The relevant cohort studies were identified by searching the electronic databases of MEDLINE, EMBASE, and CNKI. We used ''colorectal,'' ''cancer,'' ''carcinoma,'' ''ERCC1,'' ''XPD or ERCC2,'' ''polymorphism,'' ''oxaliplatin,'' ''treatment,'' or ''chemotherapy'' as key words. Inclusion criteria were patients with advanced colorectal cancer receiving oxaliplatin-based chemotherapy, evaluation of polymorphism of ERCC1 and XPD/ ERCC2, and overall response rate (ORR). In this meta-analysis, a total of seven studies were selected according to the inclusion criteria. Five studies investigated ERCC1 codon 118 polymorphisms and three studies evaluated XPD/ERCC2 codon 751 polymorphisms. For ERCC1 codon C118T polymorphism, the ORR to oxaliplatin-based chemotherapy in patients with C/C wild genotype was 77.27% and it was 69.30% for C/T and T/T variant genotype. The pooled odds ratio (OR) for C/C wild-type vs. C/T and T/T genotype was 1.11 (95% CI, 0.86-1.42; P = 0.42). For XPD/ERCC2 Lys751Gln polymorphism, the response rate was 86.58 and 67.57% in patients with the A/A and either one or two C alleles (A/C or C/C) respectively, and the pooled OR was 1.15 (95% CI, 1.01-1.30; P = 0.03). Furthermore, we chose subgroup analysis in order to find the difference between the Caucasian and Asian ethnicity. The results indicated that Oxaliplatin sensitivity was significantly associated with ERCC1 C118T polymorphism in Asian people. XPD/ERCC2 Lys751Gln polymorphism had the predictive value especially for the patients from the America and Europe.