In this study we demonstrated 1) no relationship between S100A4 and cancer-associated myositis; 2) increased S100A4 serum levels in myositis patients; 3) a relationship between S100A4 and some myositis-specific and myositis-associated autoantibodies; and 4) association between S100A4 levels and several features of myositis disease activity, particularly with extramuscular symptoms. The gene discussed is S100A4; the disease is myositis disease.