Plasma concentration and activity of matrix metalloproteinase 2 and 9 in patients with breast disease, breast cancer and at risk of developing breast cancer.

Matrix metalloproteinases (MMPs) are involved in extracellular matrix modification and associated with invasive and metastatic behavior of human malignant tumors. Specifically, MMP2 and MMP9 are implicated in both early and late processes of tumor development. It is reported that MMPs occur as inactive precursors, active enzymes or enzyme inhibitor complexes in biological samples.