Estimation of associations between MMP9 gene polymorphisms and breast cancer: Evidence from a meta-analysis.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases, which play critical roles in cancer progression and metastasis. In recent years, many researchers have been studying the relationship between MMP9 and breast cancer. However, it still remains indecisive. Therefore, we conducted a meta-analysis to draw more accurate conclusions. A total of 21 relevant documents were retrieved, including 25 case-control studies. We quantitatively analyzed the data obtained. To clarify the relationship between MMP9 polymorphism and breast cancer susceptibility under different conditions, we also made a further subgroup analysis for each locus. In summary, we discovered that MMP9 rs3918242 rendered an increased risk for breast cancer, especially among Iranians and Indians. MMP9 rs3787268 could be a protective factor. MMP9 rs17576 and MMP9 rs2250889 have no association with breast cancer risk.