MMP9 and neoplasm: The transcriptional profiling results of tumor endothelial cells from multiple studies and multiple tumor types have been compared (Aird, 2009), showing that a few overexpressed genes were shared by different tumors including matrix metalloproteinase 9 (MMP9) (ovary and breast), HEYL (breast and colon), and secreted protein acidic and rich in cysteine (SPARC) (breast and colon and brain), whereas most genes were limited to one tumor type or invasive tumors.