MMP9 and breast cancer: Our previous studies have observed that breast cancer lines, MDA-MB-231 and MDA-MB-435, that overexpressed DBGP/DARC induced the inhibition of tumorigenesis through interfering with tumor angiogenesis in rats, and this inhibition was associated with decreased expression levels of CCL2 (Chemokine C-C motif ligand 2, one of DBGP/DARC ligand), decreased microvascular density and decreased MMP-9 (matrix metalloproteinase-9) expression in xenograft tumors [13].