title: The metastasis promoting protein S100A4 levels associate with disease activity rather than cancer development in patients with idiopathic inflammatory myopathies.
abstract: BACKGROUND
  The aim was to evaluate S100A4 protein as a biomarker of disease activity and potential cancer development in patients with myositis.
  
  
  METHODS
  Serum levels of S100A4 were determined in 43 dermatomyositis (DM), 39 polymyositis (PM) and 22 cancer associated myositis (CAM) patients as well as in 77 healthy controls. The associations between S100A4 levels, inflammation, disease activity, muscle strength and cancer development were evaluated.
  
  
  RESULTS
  All myositis patients had significantly higher serum levels of S100A4 protein compared to healthy controls (median (IQR): 31.5 (17.4 to 59.5) versus 23.8 (14.5 to 33.7) ng/ml, P <0.05). In patients with PM, serum levels of S100A4 protein were significantly higher than in healthy controls (41.6 (24.2 to 123.1) versus 23.8 (14.5 to 33.7) ng/ml; P <0.001) as well as in patients with DM (26.7 (11.3 to 47.5) ng/ml; P <0.05). The levels of S100A4 were comparable between myositis with and without cancer. In all myositis patients, serum S100A4 levels correlated with MYOsitis disease ACTivity assessment (MYOACT) score (r = 0.34; P = 0.001), constitutional (r = 0.30; P = 0.003), pulmonary (r = 0.43; P = 0.0001) and extramuscular disease activity (r = 0.36; P = 0.0001), as well as with creatine phosphokinase (r = 0.27; P = 0.015) and lactate dehydrogenase (r = 0.37; P = 0.002) or c-reactive protein (CRP) levels (r = 0.24; P = 0.038). Multiple regression analysis showed significant association between S100A4 serum levels and extramuscular disease activity (β = 0.552; P = 0.002) in PM patients and with MYOACT (β = 0.557; P = 0.003) and CRP levels (β = 0.391; P = 0.029) in DM patients.
  
  
  CONCLUSIONS
  Circulating levels of S100A4 are elevated in patients with myositis and associate with several disease activity parameters, particularly with extramuscular components. No relation between S100A4 levels and presence of cancer associated myositis was found.
authors.forename: Lenka
authors.initials: L
authors.lastname: Pleštilová
authors.forename: Heřman
authors.initials: H
authors.lastname: Mann
authors.forename: Lucie
authors.initials: L
authors.lastname: Andrés Cerezo
authors.forename: Ondřej
authors.initials: O
authors.lastname: Pecha
authors.forename: Jiří
authors.initials: J
authors.lastname: Vencovský
authors.forename: Ladislav
authors.initials: L
authors.lastname: Šenolt
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism; D003402:Creatine Kinase / Q000097:blood; D003882:Dermatomyositis / Q000097:blood / Q000175:diagnosis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000097:blood* / Q000150:complications / Q000276:immunology; D009369:Neoplasms / Q000097:blood* / Q000150:complications; D017285:Polymyositis / Q000097:blood / Q000175:diagnosis; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000097:blood*; D012720:Severity of Illness Index
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C077591:S100A4 protein, human; D002097:C-Reactive Protein; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase