Association of IL-8 -251T>A and IL-18 -607C>A polymorphisms with susceptibility to breast cancer - a meta-analysis

Background: Previous studies have evaluated the association of IL-8 -251T>A and IL-18 -607C>A polymorphisms with a risk of breast cancer in different populations, but the results remain inconsistent and inconclusive. Thus, we performed this meta-analysis to explore the associations.

Methods: A comprehensive literature search in PubMed, EMBASE, Web of Science, Scopus, SciELO, SID, and CNKI for all eligible studies published up to October 1, 2020. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the intensity of associations.

Results: A total of 12 case-control studies including seven studies with 2,370 cases and 2,314 controls on IL-8 -251T>A, and five studies with 900 cases and 882 con-trols on IL-18 -607C>A polymorphism were selected. Pooled data showed that IL-8 -251T>A (AT vs. TT: OR= 1.187; 95% CI 1.038-1.356; P = 0.012) and IL-18 -607C>A polymorphisms (A vs. T: OR = 1.205; 95% CI 1.055-1.377; P = 0.006; AA vs. TT: OR = 1.379; 95% CI 1.056-1.802; P = 018; and AA vs. AT+TT: OR = 1.329; 95% CI 1.053-1.678; P = 0.017) were associated with increased risk of breast cancer in overall. Moreover, when the studies were stratified by ethnicity, the IL-8 -251T>A was significantly associated with breast cancer risk in Africans. Publication bias tests provide no evidence of presence of publication bias in a meta-analysis.

Conclusion: This meta-analysis results revealed that the IL-8 -251T>A and IL-18 -607C>A polymorphisms are associated with susceptibility to breast cancer. However, further multicenter studies with larger sample sizes in different ethnicities are required to make a better assessment of these associations.