MMP2 and rheumatoid arthritis: Several studies showed an important role of MMP-2 in RA: increased levels of MMP-2 were observed in serum and synovial fluid of patients with RA [20], increased MMP-2 production was associated with enhanced RA synovial fibroblast invasion [18], and, additionally, MMP-2 also participated in angiogenesis [7,19,48].