Thus, tumor-associated neutrophils can produce large amounts of matrix metallopeptidase 9 (MMP-9), which remodels the extracellular matrix; promotes the release of pro-angiogenic vascular endothelial growth factor (VEGF) [47,56]; and inhibits CD8+ T-cell functions via secretion of IL-10 [57], arginase 1 (which degrades extracellular arginine) [58], or reactive nitrogen species [11]. This evidence concerns the gene MMP9 and neoplasm.