MMP9 and breast cancer: Our prior studies have identified a panel of 10 urine-based protein biomarkers including Alpha-1 Antitrypsin (A1AT), angiogenin (ANG), Apolipoprotein E (APOE), Carbonic Anhydrase 9 (CA9), Interleukin-8 (IL8), matrix metalloproteinases 9 (MMP9), MMP10, plasminogen activator inhibitor-1 (PAI1), syndecan-1 (SDC1), and vascular endothelial growth factor A (VEGFA), which are significantly associated with BC [8].