Significant association between Nijmegen breakage syndrome 1 657del5 polymorphism and breast cancer risk.

Many studies were published to evaluate the association between Nijmegen breakage syndrome 1 (NBS1) 657del5 polymorphism and breast cancer risk, but the results remained inconsistent. To derive a more precise estimation on the possible association, we performed a meta-analysis of previous published studies. Case-control studies on the association between NBS1 657del5 polymorphisms and breast cancer risk were included into this meta-analysis. We used the odds ratio (OR) with 95 % confidence interval (95 % CI) to assess the strength of the association. Ten studies with a total of 25,365 subjects were identified and included into this meta-analysis. Meta-analysis of those ten studies showed that there was a significant association between NBS1 657del5 polymorphisms and breast cancer risk (pooled OR = 2.66, 95 % CI 1.82-3.90, P < 0.001). The cumulative meta-analyses showed a trend of a more significant association between NBS1 657del5 polymorphisms and breast cancer risk as data accumulated by publication year. Thus, our meta-analysis suggests that there was a significant association between NBS1 657del5 polymorphisms and breast cancer risk, and NBS1 657del5 polymorphism results in an increased risk of breast cancer.