Association between MCP-1 -2518A/G Polymorphism and Cancer Risk: Evidence from 19 Case-Control Studies

BACKGROUND Single nucleotide polymorphisms (SNPs) may affect the development of diseases. The -2518A/G polymorphism in the regulatory region of the monocyte chemo-attractant protein-1 (MCP-1) gene has been reported to be associated with cancer risk. However, the results of previous studies were inconsistent. Therefore, we performed a meta-analysis to obtain a more precise estimation of the relationship between the -2518A/G polymorphism and cancer risk. METHODOLOGY/PRINCIPAL FINDINGS We performed a meta-analysis, including 4,162 cases and 5,173 controls, to evaluate the strength of the association between the -2518A/G polymorphism and cancer risk. Odds ratio (OR) and 95% confidence intervals (95% CIs) were used to assess the strength of association. Overall, the results indicated that the -2518A/G polymorphism was not statistically associated with cancer risk. However, sub-group analysis revealed that individuals with GG genotypes showed an increased risk of cancer in digestive system compared with carriers of the A allele (GG vs. AA: OR = 1.43, 95%CI = 1.05-1.96, P(heterogeneity) = 0.08; GG vs. AG/AA OR = 1.29, 95%CI = 1.02-1.64, P(heterogeneity) = 0.14). In addition, the increased risk of GG genotype was also observed in Caucasians (GG vs. AG/AA OR = 1.81, 95%CI = 1.10-2.96, P(heterogeneity) = 0.02). CONCLUSION This meta-analysis suggests that the MCP-1 -2518A/G polymorphism may have some relation to digestive system cancer susceptibility or cancer development in Caucasian. Large-scale and well-designed case-control studies are needed to validate the findings.