The role of neutrophils in tumor angiogenesis has been previously reviewed (58, 59), and the mechanisms include releasing a variety of proteases (such as MMP9), directly secreting a multitude of soluble pro-angiogenic factors [such as vascular endothelial growth factor (VEGF)], and through intimate cell-to-cell interactions with endothelial cells. The gene discussed is MMP9; the disease is neoplasm.