CXCL12 and neoplasm: The presence of those macrophages provide a road map for the homing of circulating tumor cells (CTCs) into the PMNs with enhanced expression of chemokines such as stromal derived factor (SDF)-1 and Ang-1 and remodel the ECM to the tumor cell-favoring direction by secreting ECM-shaping enzymes like MMPs, integrins, and lysyl oxidase (LOX), most of which have been mentioned above as critical inducers of angiogenesis, EMT, and extravasation [118–121].