Plasma matrix metalloproteinase-9 level in invasive ductal breast carcinoma patients

Matrix metalloproteinases (MMPs) are members of a family of zinc-endopeptidases, which play a key role in extracellular matrix degradation in human cancer progression including breast cancer. Plasma MMP-9 level should provide a marker for differentiation between benign and malignant breast cancer. Here, plasma MMP-9 levels of invasive ductal breast cancer (IDC) patients (n = 108)and those of volunteers with mammography BIRADS categories 1-4 (n =211) were determined using an ELISA technique. Median [25-75% interquartile range (IQR)]concentration of plasma MMP-9 of IDC patients is significantly higher than those of volunteers in all BIRADS categories (13 (10-15) vs 9 (7-11) ng/ml) (p-value <0.001). In addition, MMP-9 level of IDC patients is also significantly higher than that of volunteers with mammography BIRADS category 1-4 (9.1 (8.7-9.3), 8.8 (7.9-9.9), 9.7 (8.4-10.5), and 9.8 (7.8-11.9) ng/ml, respectively) (p-value <0.001). Receiver-operator curve analysis for MMP-9 concentrations between IDC patients and volunteers in all BIRADS categories showed an area under curve of 0.829 (95% confidence interval: 0.783-0.869) (p-value <0.001) and a cutoff value of 10.5 ng/ml (76% sensitivity and 82% specificity); however, association between plasma MMP-9 levels and clinicopathological parameters of IDC patients is not significant, and a larger cohort is needed to determine the potential usefulness of such association studies. In conclusion, plasma matrix metalloproteinase-9 level serves as a convenient biomarker for distinguishing between women with benign and malignant breast cancer but association of MMP-9 levels with clinicopathological parameters needs further investigation.