19 (1.38-3.47) 0.22 1.24 (0.11-13.84) – 2.15 (1.37-3.38) 0.27 1.07 (0.10-11.89) –    Mixed 1 58/528 1.44 (0.79-2.64) – 1.35 (0.30-6.11) – 1.43 (0.80-2.56) – 1.22 (0.27-5.48) – a Number of comparisons b P value of Q-test for heterogeneity test. Random-effects model was used if the P value <0.10; otherwise, fixed-effects model was used Publication bias Begg's funnel plot was used to identify the potential publication bias of literatures on breast cancer, and the results did not show any evidence of publication bias in any comparison model (P > 0.05). Discussion Previous studies have inconclusive results about the association between ATM D1853N polymorphism and breast cancer

risk, which might be caused by relatively small sample size in a single study. Meta-analysis offers a rational and helpful way to solve this practical problem by combination the findings from selleck independent studies. In the current meta-analysis, we cumulated the data from nine case-control studies to explore the association between ATM D1853N polymorphism and breast cancer risk. No significant association between this polymorphism and breast cancer risk was observed

in the overall study populations. Our result was consistent with the finding from a previous meta-analysis showing that another polymorphism of ATM (S49C, rs1800054) was not significantly associated with breast cancer susceptibility [28]. This finding indicates that the ATM D1853N polymorphism is not a risk factor for developing breast cancer, although a significantly increased risk

of breast cancer in ATM-heterozygous carriers has been reported [1, 13–18]. Mizoribine order After subgroup analyses according to ethnicity, we found that the ATM D1853N polymorphism was associated with a significantly increased risk of breast cancer in South American population (heterozygote comparison and dominant model) but not in European and mixed populations. The reason for these discrepancies is not very clear. There are, however, some possible selleck products reasons. Firstly, the ATM D1853N polymorphism may present with different frequencies in different populations and as a result may be associated with different degrees of breast cancer risk among different ethnic populations. Secondly, the genotype distribution in the controls of a South American study was departed from check details Hardy-Weinberg equilibrium [27], indicating that there was a high risk of selection bias because the controls may not be representative of the general population very well. Thirdly, the positive association might have occurred by chance due to the insufficient statistical power with only two South American studies eligible in this meta-analysis [27, 29]. Therefore, additional studies with larger sample size are of great importance to clarify this finding. Some limitations of this meta-analysis should be taken into consideration.