title: Immunohistochemical expression of matrix metalloproteinase-2 and -9 in melanocytic nevi is altered by ultraviolet B.
abstract: BACKGROUND
  Ultraviolet B (UVB) radiation can cause morphological and biological alterations similar to those of melanoma in situ in irradiated melanocytic nevi. matrix metalloproteinase (MMP-2) and -9 appear to be involved with tumour invasion, the formation of metastases and neoangiogenesis in melanomas. The effects of UVB on the immunohistochemical expression of gelatinases in different cell types in melanocytic nevi have not been completely studied.
  
  
  OBJECTIVE
  Evaluate the effects of UVB on the immunohistochemical expression of MMP-2 and -9 in different cell types in melanocytic nevi.
  
  
  METHODS
  Forty-two melanocytic nevi had one half irradiated with 2 MEDs of UVB and were excised 1 week later. Three different observers compared the intensity of the immunohistochemical expression of gelatinases in keratinocytes, melanocytes, endothelial cells and fibroblasts on the irradiated (IS) and non-irradiated sides (NIS).
  
  
  RESULTS
  All the cell types showed an increase in the expression of MMP-2 on the IS, especially the epidermal melanocytes. No significant increase in the expression of MMP-9 in keratinocytes was detected on the IS; significant increase was observed in all the remaining cells.
  
  
  CONCLUSIONS
  One single irradiation of UVB increases the immunohistochemical expression of gelatinases in almost all evaluated cell lines, with the exception of MMP-9 in keratinocytes.
authors.affiliation: Department of Dermatology, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. rbakos@portoweb.com.br
authors.forename: Renato Marchiori
authors.initials: RM
authors.lastname: Bakos
authors.forename: Lucio
authors.initials: L
authors.lastname: Bakos
authors.forename: Maria Isabel Albano
authors.initials: MI
authors.lastname: Edelweiss
authors.forename: André
authors.initials: A
authors.lastname: Cartell
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Mariante
authors.forename: Nathália Costaguta Matas Soles
authors.initials: NC
authors.lastname: Masiero
mesh_terms: D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009508:Nevus, Pigmented / Q000201:enzymology*; D012867:Skin / Q000201:enzymology / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9