MMP14 and ovarian benign neoplasm: Membrane type 1 matrix metalloproteinase (MT1-MMP or MMP-14) is a transmembrane collagenase that is not detected in normal ovarian surface epithelium nor in benign ovarian tumors, but is widely expressed in ovarian carcinomas of all histologic types, with enhanced expression in metastases relative to primary tumors [16, 35-37].