Neutrophils have been shown to accelerate tumorigenesis by releasing genotoxic DNA substances, stimulating tumor cell proliferation by secreting PGE2, activating tumor angiogenesis by releasing Bv8 and matrix metalloproteinase 9 (MMP9), and promoting tumor cell migration, invasion, and extracellular matrix degradation (30). This evidence concerns the gene MMP9 and neoplasm.