These proteins or their proteolytic fragments may either promote or inhibit cancer progression, e.g., the cleavage of fibronectin and laminin may be involved in cell invasion [25], [26], IGFBP-3 is associated with cell proliferation [44], [54], galectin-3 is involved in several processes including cell adhesion, proliferation, apoptosis and angiogenesis [55], [56] and plasminogen-derived angiostatin-like fragments inhibit angiogenesis [20]. This evidence concerns the gene PLG and cancer.