Associations between XPD polymorphisms and risk of breast cancer: a meta-analysis

Studies on polymorphisms of Xeroderma Pigmentosum Group D Protein (XPD) and breast cancer risk are inconclusive. To elucidate the role of XPD genotypes, all available studies were considered in this meta-analysis. The study provided 11,362/10,622 cases/controls for XPD K751Q and 9010/9873 cases/controls for XPD D312N, respectively. Overall, no apparent effects of 751Q allele compared to 751K on breast cancer risk was found in all subjects [RE OR = 1.04, 95% confidence interval (CI) (0.97-1.10), P = 0.28]. Insignificant effects were also found under other genetic contrasts (homologous contrast, dominant model, and recessive model). However, the 751Q allele showed significantly increased risk in Caucasians [FE OR = 1.05, 95% CI (1.00-1.11), P = 0.035]. In addition, insignificant risk effects of D312N polymorphism on breast cancer susceptibility were observed in all subjects under any genetic contrast, but protective effects of 312NN genotype were observed under recessive model [P = 0.02, OR = 0.53, 95% CI (0.32, 0.90)] and homozygote contrast [P = 0.03, OR = 0.55; 95% CI (0.32, 0.96)] in Asians. In summary, our meta-analysis suggested 312N allele might act as a recessive allele in its association with breast cancer and the 751Q allele may play a plausible role in breast cancer development whereas the ethnic background should be carefully concerned in further studies.