Current evidence on the relationship between four polymorphisms in the matrix metalloproteinases (MMP) gene and breast cancer risk: a meta-analysis

The matrix metalloproteinases (MMP) can degrade various components of the extracellular matrix and its functional genetic polymorphisms may be associated with breast cancer risk. However, this relationship remains controversial. A meta-analysis was conducted in order to investigate the potential association between four polymorphisms in the MMP gene and breast cancer risk. A database search yielded a total of 9 studies involving 2,597 cases and 2,618 controls. Four polymorphisms were included in the meta-analysis: MMP-1 -1607 2G/1G (rs1799750), MMP-2 -1306 C/T (rs243865), MMP-3 -1171 6A/5A (rs3025058) and MMP-9 -1562 C/T (rs3918242). Crude odds ratios (OR) with 95% confidence intervals (CI) were used to assess the strength of association. When all the studies were pooled into the meta-analysis, we found that breast cancer cases had a significantly higher frequency of CC genotype (OR = 1.27, 95% CI = 1.10, 1.47; P = 0.001) and lower frequency of CT genotype (OR = 0.78, 95% CI = 0.67, 0.91; P = 0.001) of MMP-2. No significant difference was found in any genotype of MMP-1, MMP-3 or MMP-9. In conclusion, this meta-analysis suggested that MMP-2 -1306 C/T polymorphism may contribute to breast cancer susceptibility. More studies were needed especially in Asians in the future.