In addition, ECM synthesized by normal fibroblasts treated with NM exhibited increased stability and significantly reduced the osteosarcoma cell growth rate, invasive activity (MMP-2 and -9 secretion and Matrigel invasion) and adhesion to collagen I and other substrates, suppressing tumor growth independently of the immune system function and inhibiting critical steps in cancer metastasis (22). This evidence concerns the gene MMP2 and osteosarcoma.