MMP9 and neoplasm: Neutrophils are a major component of leukocyte and can induce several procancer factors, including neutrophil elastase, matrix metalloprotein 9 (MMP9), and vascular endothelial growth factor (VEGF), and therefore are involved in the remodeling of the extracellular matrix and promotion of angiogenesis and tumor development [19, 28, 29].