APEX1 and breast cancer: When all 7 studies were pooled into the meta-analysis, there was no evidence of significant association between APEX1 Asp148Glu polymorphism and breast cancer risk (Glu/Glu vs. Asp/Asp: OR = 0.948, 95% CI = 0.817–1.101, P = 0.486; Asp/Glu vs. Asp/Asp: OR = 0.975, 95% CI = 0.790–1.204, P = 0.814; Glu/Glu + Asp/Glu vs. Asp/Asp: OR = 0.959, 95% CI = 0.803–1.146, P = 0.646; Glu/Glu vs. Asp/Glu + Asp/Asp: OR = 0.961, 95% CI = 0.846–1.091, P = 0.540).