The associations between two polymorphisms in the interleukin-10 gene promoter and breast cancer risk

The association between single-nucleotide polymorphisms (SNPs) in the interleukin-10 (IL-10) gene promoter and breast cancer risk is still ambiguous. We here performed a meta-analysis based on the evidence currently available from the literature to make a more precise estimation of the relationship between two genetic variants in the IL-10 gene promoter, -1082A > G (rs1800896) and -592C > A (rs1800872), and breast cancer. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the corresponding strengths of association under the codominant, dominant, and recessive models. A total of ten studies (4,181 cases and 4,384 controls) were eligible for meta-analysis. There were six studies with 3,032 cases and 3,190 controls for rs1800872, and eight studies with 1,636 cases and 1,670 controls for rs1800896. Meta-analysis showed that neither of the two polymorphisms had any association with increased breast cancer risk (for rs1800896: OR = 1.060, 95% CI = 0.785-1.432 in the dominant model, and OR = 1.152, 95% CI = 0.958-1.386 in the recessive model; and for rs1800872: OR = 0.952, 95% CI = 0.859-1.056 in the dominant model, and OR = 0.892, 95% CI = 0.741-1.072 in the recessive model). The results did not change when the analyses were restricted in Caucasians, or in the studies fulfilling Hardy-Weinberg equilibrium, or according to source of controls. In outlier analysis, no individual study affected the overall OR dominantly, since omission of any single study made no material huge difference. In conclusion, the present meta-analysis suggests a lack of association between the two SNPs (rs1800896 and rs1800872) in the IL-10 gene promoter and breast cancer risk. Further studies, either with larger sample size or regarding other SNPs/haplotypes within the IL-10 gene, are needed to clarify the role of IL-10 in breast carcinogenesis.