title: Examination of oral cancer biomarkers by tissue microarray analysis.
abstract: OBJECTIVE
  To validate the DNA microarray results on a subset of genes that could potentially serve as biomarkers of oral squamous cell carcinoma (OSCC) by examining their expression with an alternate quantitative method and by assessing their protein levels.
  
  
  METHODS
  Based on DNA microarray data from our laboratory and data reported in the literature, we identified 6 potential biomarkers of OSCC to investigate further. We used quantitative real-time polymerase chain reaction to examine expression changes of CDH11, MMP3, SPARC, POSTN, TNC, and TGM3 in OSCC and histologically normal control tissues. We further examined validated markers at the protein level by immunohistochemical analysis of OSCC tissue microarray sections.
  
  
  RESULTS
  Quantitative real-time polymerase chain reaction analysis revealed upregulation of CDH11, SPARC, POSTN, and TNC gene expression and decreased TGM3 expression in OSCC tissue compared with control tissue; MMP3 was not found to be differentially expressed. In tissue microarray immunohistochemical analyses, SPARC (secreted protein, acidic, rich in cysteine), periostin, and tenascin C exhibited increased protein expression in tumor tissue compared with control tissue, and their expression was primarily localized within tumor-associated stroma rather than tumor epithelium. Conversely, transglutaminase 3 protein expression was found only within keratinocytes in control tissue and was significantly downregulated in cancer cells.
  
  
  CONCLUSIONS
  Of 6 potential gene markers of OSCC, initially identified by DNA microarray analyses, differential expression of CDH11, SPARC, POSTN, TNC, and TGM3 were validated by quantitative real-time polymerase chain reaction. Differential expression and localization of proteins encoded by SPARC, POSTN, TNC, and TGM3 were clearly shown by tissue microarray immunohistochemical analysis.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University ofWashington, Seattle, WA, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Choi
authors.forename: C Diana
authors.initials: CD
authors.lastname: Jordan
authors.forename: Eduardo
authors.initials: E
authors.lastname: Mendez
authors.forename: John
authors.initials: J
authors.lastname: Houck
authors.forename: Bevan
authors.initials: B
authors.lastname: Yueh
authors.forename: D Gregory
authors.initials: DG
authors.lastname: Farwell
authors.forename: Neal
authors.initials: N
authors.lastname: Futran
authors.forename: Chu
authors.initials: C
authors.lastname: Chen
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016022:Case-Control Studies; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D007150:Immunohistochemistry; D016014:Linear Models; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D009062:Mouth Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D015676:Osteonectin / Q000378:metabolism; D015203:Reproducibility of Results; D019063:Tenascin / Q000378:metabolism; D046888:Tissue Array Analysis; D011503:Transglutaminases / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D015815:Cell Adhesion Molecules; D015676:Osteonectin; C512835:POSTN protein, human; D019063:Tenascin; C086960:osteoblast cadherin; C498712:TGM3 protein, human; D011503:Transglutaminases; C511768:MMP3 protein, human; D019278:Matrix Metalloproteinase 3