MMP9 and cancer: MMP-14 is also related to cancer formation and progression, and its downregulation may be of importance in the endometrium [61], which may be in accordance with the findings reported here, where it was decreased in PCOS and was BMI-dependent; however, together with the changes seen for MMP-9 and MMP-2, it may contribute to the changes in type 4 collagen, suggesting basement membrane alterations in the pathogenesis of PCOS [50].