The pro-tumor effect of M2 type macrophages is associated with their production of MMPs, urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), and others, of which MMP-9 has been proved to have complex effects, including induction of the angiogenic switch and release of growth factors [35], [36]. The gene discussed is PLAUR; the disease is neoplasm.