MMP9 and osteosarcoma: Based on these studies, we hypothesized that (1) the reported effects of glucosamine are most probably not limited to the reported sarcoma cell types and may extend to osteosarcoma cells, (2) glucosamine suppresses the basal expression of MMPs in the absence of specific MMP inducers such as concanavalin A or PMA, and (3) glucosamine potentially suppresses MMP-3, MMP-9 and MMP-2 expression to different extents.