MMP9 and neoplasm: MMPs, also designated matrixins, are proteolytic enzymes containing a signal peptide, a propeptide, a catalytic domain, and a hemopexin domain[4,5] capable of degrading the extracellular matrix, which is essential for tumor invasion.[6] MMP-9 (gelatinase b) and MMP-2 (gelatinase a), classified as type IV collagenases, can degrade Collagen Types IV particularly,[7] which is the prominent component of the basement membrane.[8] Inasmuch as the basement membrane seems to play a critical role in tumor invasion,[7] expression MMP-9 and -2 is conceived as an important sign of the tumor invasion.