title: Repression of genes involved in melanocyte differentiation in uveal melanoma.
abstract: OBJECTIVE
  Uveal melanoma (UM) has been the subject of intense interest due to its distinctive metastatic pattern, which involves hematogenous dissemination of cancerous cells toward the liver in 50% of patients. To search for new UM prognostic markers, the Suppressive Subtractive Hybridization (SSH) technique was used to isolate genes that are differentially expressed between UM primary tumors and normal uveal melanocytes (UVM).
  
  
  METHODS
  A subtracted cDNA library was prepared using cDNA from uncultured UM primary tumors and UVM. The expression level of selected genes was further validated by cDNA microarray, semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), and immunofluorescence analyses.
  
  
  RESULTS
  One hundred-fifteen genes were identified using the SSH technique. Microarray analyses comparing the gene expression profiles of UM primary tumors to UVM validated a significant differential expression for 48% of these genes. The expression pattern of selected genes was then analyzed by semi-quantitative RT-PCR and was found to be consistent with the SSH and cDNA microarray findings. A down-regulation of genes associated with melanocyte differentiation was confirmed in UM primary tumors. Presence of undifferentiated cells in the UM was demonstrated by the expression of stem cell markers ATP-binding cassette sub-family G member 2 (ABCG2) and octamer-binding protein 4 (OCT4).
  
  
  CONCLUSIONS
  We demonstrated that the SSH technique is efficient to detect differentially expressed genes between UM and UVM. The genes identified in this study represent valuable candidates for further functional analysis in UM and should be informative in studying the biology of this tumor. In addition, deregulation of the melanocyte differentiation pathway revealed the presence of UM cells exhibiting a stem cell-like phenotype.
authors: LOEX/CUO-recherche, Centre hospitalier affilié universitaire de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, 1050 Chemin Ste-Foy,Québec, QC, Canada.
authors: Marjorie-Allison
authors: MA
authors: Bergeron
authors: Sophie
authors: S
authors: Champagne
authors: Manon
authors: M
authors: Gaudreault
authors: Alexandre
authors: A
authors: Deschambeault
authors: Solange
authors: S
authors: Landreville
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D055028:Comparative Genomic Hybridization / Q000379:methods; D018076:DNA, Complementary; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D015723:Gene Library; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000401:mortality / Q000556:secondary; D008297:Male; D008544:Melanocytes / Q000378:metabolism* / Q000473:pathology; D008545:Melanoma / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics*; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D014602:Uvea / Q000378:metabolism* / Q000473:pathology; D014604:Uveal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D000098943:Uveal Melanoma
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D014408:Biomarkers, Tumor; D018076:DNA, Complementary; D009363:Neoplasm Proteins; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human