title: Matrix metalloproteinase-9 (MMP-9) expression in childhood osseous osteosarcoma.
abstract: BACKGROUND
  Over 80% of patients with osteosarcoma treated with excision alone develop pulmonary metastases, suggesting that the majority of patients with this disease harbor "micrometastases" at diagnosis. There are no histologic or molecular variables which can predict the presence or absence of micrometastasis. Matrix metalloproteinases (MMPs) are a class of matrix- and basement membrane-degrading enzymes whose expression is associated with tumor cell invasive and metastatic behavior. One of these enzymes, MMP-9 or gelatinase B, is expressed in developing and remodeling bone and in osteosarcoma cell lines. We speculated that MMP-9 expression might be associated with the micrometastatic behavior of osteosarcoma.
  
  
  METHODS
  We examined a series of pediatric primary osseous osteosarcomas and metastases for the expression of MMP-9, using a monoclonal antibody.
  
  
  RESULTS
  We found intense MMP-9 immunostaining in most tumor cells in all samples of pretreatment osteosarcomas. In all postchemotherapy resection samples, tumor cells stained similarly, but there were fewer positively staining cells overall. In 4 of 5 metastastic lesions examined, intense immunostaining for MMP-9 was detected.
  
  
  CONCLUSIONS
  These results suggest that MMP-9 expression is common in osteosarcoma, and that further study of the role of MMP-9 in pediatric osteosarcoma behavior is warranted.
authors.affiliation: Department of Pediatrics, Children's Hospital of Philadelphia, PA 19104, USA. Himelstein@kermit.oncol.chop.edu
authors.forename: B P
authors.initials: BP
authors.lastname: Himelstein
authors.forename: N
authors.initials: N
authors.lastname: Asada
authors.forename: M R
authors.initials: MR
authors.lastname: Carlton
authors.forename: M H
authors.initials: MH
authors.lastname: Collins
mesh_terms: D001859:Bone Neoplasms / Q000201:enzymology* / Q000473:pathology*; D002648:Child; D017364:Collagenases / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008175:Lung Neoplasms / Q000556:secondary; D008297:Male; D020780:Matrix Metalloproteinase 9; D012516:Osteosarcoma / Q000201:enzymology* / Q000473:pathology*
chemical_list: D017364:Collagenases; D020780:Matrix Metalloproteinase 9