title: c-Met expression in tall cell variant papillary carcinoma of the thyroid.
abstract: BACKGROUND
  Tall cell variant papillary carcinoma of the thyroid demonstrates unusually aggressive clinical behavior compared with the usual form of papillary thyroid carcinoma. The proto-oncogene c-met encodes a tyrosine kinase receptor known to influence cell invasion. This current study examined c-Met expression in tall cell variant tumors compared with other types of papillary thyroid carcinoma and benign thyroid disease.
  
  
  METHODS
  c-Met expression in 60 archived thyroid specimens was evaluated by immunohistochemical staining.
  
  
  RESULTS
  Tall cell variant specimens expressed significantly greater levels of c-Met than other forms of papillary thyroid carcinoma and benign thyroid disease (P < 0.0001). c-Met expression was significantly different for the following pairs of histologies: tall cell variant versus usual papillary carcinoma of the thyroid (P < 0.0001), tall cell variant versus follicular variant papillary thyroid carcinoma (P < 0.0001), tall cell variant versus benign thyroid (P < 0.0001), and usual papillary carcinoma of the thyroid versus benign thyroid (P = 0.005). In addition, for all types of papillary carcinomas evaluated, c-Met expression was significantly higher in specimens with extracapsular spread (P = 0.01) and skeletal muscle invasion (P = 0.02), and approached significance for specimens with lymphatic invasion (P = 0.06). After adjusting for extracapsular spread, c-Met expression was still found to be associated significantly with tall cell histology (P < 0.0001).
  
  
  CONCLUSIONS
  c-Met expression is a significant marker for tall cell variant papillary carcinoma of the thyroid and its invasive behavior. This finding may explain the unusually aggressive behavior of this tumor and suggests a role for c-Met in the early identification of patients with tall cell variant thyroid disease.
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000032:analysis*; D002291:Carcinoma, Papillary / Q000235:genetics / Q000473:pathology*; D016022:Case-Control Studies; D046508:Culture Techniques; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D011336:Probability; D011379:Prognosis; D000090063:Proto-Oncogene Mas; D019859:Proto-Oncogene Proteins c-met / Q000032:analysis* / Q000235:genetics; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013959:Thyroid Diseases / Q000235:genetics / Q000473:pathology; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D019859:Proto-Oncogene Proteins c-met