MMP-9 expression was downregulated by doxycycline 100 μM in chondrosarcoma and liposarcoma by 96 and 86%, respectively, while fibrosarcoma MMP-9 expression was completely blocked at 25 μM. Sensitivity of cell lines to EGCG varied in MMP-2 expression, with total block at 25 μM in synovial sarcoma, 50 μM in fibrosarcoma and liposarcoma and 96% block in chondrosarcoma at 100 μM. PMA-induced MMP-9 expression was blocked by EGCG at 25 μM in synovial sarcoma and 100 μM in fibrosarcoma and virtually blocked at 100 μM in chondrosarcoma and liposarcoma. This evidence concerns the gene MMP9 and synovial sarcoma.