title: Immunohistochemical expression of neurotrophic tyrosine kinase receptors 1 and 2 in lung carcinoma: potential discriminators between squamous and nonsquamous subtypes.
abstract: BACKGROUND
  The neurotrophic tyrosine kinase receptors NTRK1 and NTRK2 have been implicated in the pathogenesis of lung carcinomas. NTRK receptor expression has been reported in lung carcinomas; however, the clinical utility of immunohistochemical expression of these receptors is unclear.
  
  
  OBJECTIVE
  To compare the immunohistochemical expression profiles of NTRK1 and NTRK2 in various histologic subtypes of lung carcinomas and correlate with patient outcome.
  
  
  METHODS
  Six hundred eighty-six unique lung cancer cases (including squamous cell carcinoma, adenocarcinoma, large cell carcinoma, small cell carcinoma, and carcinoid tumor) with clinical outcome data in tissue microarray format were immunohistochemically stained for NTRK1 and NTRK2 using commercially available antibodies, automated immunostaining, and standard protocols.
  
  
  RESULTS
  Expression of both NTRK1 and NTRK2 correlates strongly with squamous histology. NTRK1 and NTRK2 are highly specific markers (1: 92.8%, 2: 96.4%) of squamous lung carcinoma when compared with the other carcinoma subtypes, including adenocarcinoma. Positive NTRK2 staining in squamous carcinoma correlates with improved disease-specific survival (P < .001) and overall survival (P  =  .047).
  
  
  CONCLUSIONS
  NTRK1 and NTRK2 are potentially useful immunohistochemical markers that may be particularly helpful in separating squamous cell carcinoma from adenocarcinoma.
authors.affiliation: Centre for Translational and Applied Genomics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada. Jefferson.Terry@vch.ca
authors.forename: Jefferson
authors.initials: J
authors.lastname: Terry
authors.forename: Alessandro
authors.initials: A
authors.lastname: De Luca
authors.forename: Samuel
authors.initials: S
authors.lastname: Leung
authors.forename: Graeme
authors.initials: G
authors.lastname: Peacock
authors.forename: Yuzhuo
authors.initials: Y
authors.lastname: Wang
authors.forename: W Mark
authors.initials: WM
authors.lastname: Elliot
authors.forename: David
authors.initials: D
authors.lastname: Huntsman
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002277:Carcinoma / Q000145:classification / Q000378:metabolism*; D003937:Diagnosis, Differential; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification / Q000378:metabolism*; D018307:Neoplasms, Squamous Cell / Q000378:metabolism*; D020917:Receptor, trkA / Q000378:metabolism*; D020813:Receptor, trkB / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D020917:Receptor, trkA; D020813:Receptor, trkB