title: EGFR and Ki-67 expression in oral squamous cell carcinoma using tissue microarray technology.
abstract: OBJECTIVE
  Our aim was to validate the use of tissue microarrays (TMA) in oral squamous cell carcinomas (OSCC) to analyse epidermal growth factor receptor (EGFR) and Ki-67 expression. We also analysed the relationship that the expression of these markers may have with clinical, pathological and survival variables.
  
  
  METHODS
  The study sample comprised 39 unselected patients diagnosed and treated for OSCC. We analysed Ki-67 and EGFR expression by immunohistochemistry on formalin-fixed, paraffin-embedded surgical specimens. Whole sections (WS) were compared with double 1.5 mm core-tissue microarrays.
  
  
  RESULTS
  High EGFR expression was observed both on TMA (in 98% of the cases) and WS (in 100% of the cases) with substantial agreement kappa value (0.720). EGFR expression was not significantly associated with clinical, pathological and survival variables on TMA and WS. Ki-67 analysis showed a Spearman correlation of 0.741 with a Ki-67 mean labelling index of 45% in TMA and 56.8% in WS. We found a significant relationship between gender and Ki-67 labelling index on WS (P = 0.022) and TMA (P = 0.002). Clinical stage was the only parameter in multivariate analysis that had a significant predictive value.
  
  
  CONCLUSIONS
  We demonstrate that dual 1.5 mm core TMA is a valid, rapid, economical and tissue-saving way to study OSCC biopsies and that it presents strong correlation with the WS. EGFR overexpression in OSCC suggests that these tumours may be a candidate for therapy investigation directed to EGFR.
authors.affiliation: Department of Oral Surgery and Oral Medicine, Higher Institute of Health Sciences, Paredes, Portugal. lmonteiro_md@hotmail.com
authors.forename: Luís Silva
authors.initials: LS
authors.lastname: Monteiro
authors.forename: Márcio
authors.initials: M
authors.lastname: Diniz-Freitas
authors.forename: Tomás
authors.initials: T
authors.lastname: Garcia-Caballero
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Forteza
authors.forename: Máximo
authors.initials: M
authors.lastname: Fraga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000556:secondary; D066246:ErbB Receptors / Q000032:analysis*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009060:Mouth Floor / Q000473:pathology; D009062:Mouth Neoplasms / Q000473:pathology*; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012737:Sex Factors; D015996:Survival Rate; D046888:Tissue Array Analysis; D014062:Tongue Neoplasms / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D066246:ErbB Receptors