Clinically oriented research on S100A4 has been largely focused on its cancer metastasis-promoting properties (3, 7, 8), and its role in promoting pathological inflammation in rheumatoid arthritis (9, 10), cardiovascular disease (11), fibrotic diseases (12, 13), and experimental autoimmune encephalomyelitis (14). Here, S100A4 is linked to rheumatoid arthritis.