By producing different types of enzymes and proteases, such as matrix metalloproteinases (MMPs), in particular MMP2 and MMP9, plasmin, urokinase plasminogen activator (uPA), and cathepsins [85–87] (Figure 2), TAMs can regulate the degradation of the extracellular matrix (ECM) and dictate tumour invasion and the metastatic process [19]. This evidence concerns the gene PLAU and neoplasm.