High expression of transcription factor SOX5 was detected in RA-FLS and MMP-9 expression was inhibited from the knockdown model of SOX5 in CIA mice, suggesting thatSOX5 at least a part plays a pivotal role in mediating migration and invasion of FLS by regulating MMP-9 expression in RA that was confirmed inhibited in the joint tissue and reduced pannus migration and invasion into the cartilage [150]. Here, MMP9 is linked to rheumatoid arthritis.