MMP2 and neoplasm: Recent reports have demonstrated the neutrophils’ pro-tumor role in the tumor microenvironment through the secretion of proteases such as matrix metalloproteinases (MMP) 9 and MMP2 as well as inflammatory factors including interleukin (IL)-1β [10,21], CC family ligands [10,22], and the formation of neutrophil extracellular traps (NETs) [10,23,24,25,26,27,28,29].