The cells themselves produceenzymes either membrane-bound (e.g., MT-MMPs) or secreted to modulate theadjacent extracellular matrix [33].The expression of collagenases MMP-14, MMP-12, and MMP-9 increase theinvasiveness of tumor cells migrating through a collagen fiber network orthrough a Boyden-chamber (transwell membrane) [33].MMP-9 cooperates with the αvβ3 integrin in supporting breastcarcinoma cell migration using transwell membrane assay [20]. Here, MMP9 is linked to breast carcinoma.