title: Different pattern of matrix metalloproteinases expression in alveolar versus embryonal rhabdomyosarcoma.
abstract: OBJECTIVE
  The matrix metalloproteinases (MMPs), a family of enzymes that degrade the extracellular matrix (ECM), are important in neoplastic cell invasion and metastasis. Data for rhabdomyosarcoma (RMS), the most frequent soft tissue sarcoma of childhood, are lacking. The aim of this study was to assess their expression in this tumor and to evaluate the correlation with clinicopathologic parameters.
  
  
  METHODS
  Immunohistochemical expression of MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, TIMP-1, and TIMP-2 was investigated in 33 human RMSs, 12 alveolar, and 21 embryonal histologic subtypes (12 high risk and 9 low/standard risk). Evaluation of the results was based on the percent of positive neoplastic cells and on staining intensity (negative, moderate, and strong). In situ zymography was carried out on 4 frozen RMS samples (2 alveolar and 2 high-risk embryonal).
  
  
  RESULTS
  Alveolar type showed a stronger MMP-1, -2 and -9 expression in comparison with embryonal (P = .006, P <.001, and P <.001, respectively). Intratumoral vessels and perivascular ECM were positive for MMP-9 in the majority of RMSs. Both TIMPs had negative results.
  
  
  CONCLUSIONS
  Gelatinases MMP-2 and MMP-9 and collagenase MMP-1 overexpression seem to contribute to the more aggressive phenotype of alveolar rhabdomyoblastic cells. Further characterization of the expression of MMPs and consequent utilization of their inhibitors in aggressive alveolar RMSs might lead to the development of novel anticancer therapies.
authors.affiliation: Department of Pathology, Children's Hospital Bambino Gesu, Research Institute, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Diomedi-Camassei
authors.forename: Renata
authors.initials: R
authors.lastname: Boldrini
authors.forename: Lucilla
authors.initials: L
authors.lastname: Ravà
authors.forename: Alberto
authors.initials: A
authors.lastname: Donfrancesco
authors.forename: Camillo
authors.initials: C
authors.lastname: Boglino
authors.forename: Elisa
authors.initials: E
authors.lastname: Messina
authors.forename: Carlo
authors.initials: C
authors.lastname: Dominici
authors.forename: Francesco
authors.initials: F
authors.lastname: Callea
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D020782:Matrix Metalloproteinases / Q000032:analysis / Q000096:biosynthesis*; D018232:Rhabdomyosarcoma, Alveolar / Q000378:metabolism* / Q000473:pathology; D018233:Rhabdomyosarcoma, Embryonal / Q000378:metabolism* / Q000473:pathology
chemical_list: D020782:Matrix Metalloproteinases