title: The Value of Cytokeratin 5/6, p63 and Thyroid Transcription Factor-1 in Adenocarcinoma, Squamous Cell Carcinoma and Non-Small-Cell Lung Cancer of the Lung.
abstract: OBJECTIVE
  It is now important to distinguish between adenocarcinoma and squamous cell carcinoma of the lung because of target-specific treatments. Our study aimed to study the efficiency of Thyroid Transcription Factor-1 (TTF-1), cytokeratin 5/6 (CK5/6) and p63 in distinguishing between adenocarcinoma and squamous cell carcinoma and to study the contribution of these markers to the diagnosis in non-small cell lung cancer.
  
  
  METHODS
  Immunohistochemically, TTF-1, CK 5/6 and p63 were used in 72 cases of squamous cell carcinoma, 19 cases of adenocarcinoma, and 29 cases of non-small cell lung cancer whose final diagnosis was decided with the subsequent resection material. The specificity, sensitivity, and positive and negative predictive value were calculated for each marker.
  
  
  RESULTS
  TTF-1 positivity was seen in none of the 72 squamous cell carcinomas but in all of 19 adenocarcinoma cases. CK5/6 negativity was seen in all cases of adenocarcinoma and in two cases of squamous cell carcinoma. p63 was positive in all squamous cell carcinomas and in 4 adenocarcinomas. Cytokeratin 5/6, p63 positivity and TTF-1 negativity were observed in 17 non-small cell lung cancers whose final diagnosis was squamous cell carcinoma. None of the 12 non-small cell lung cancers whose final diagnosis was adenocarcinoma exhibited positive staining for CK5/6. However, p63 staining was not seen in the biopsy but was focal in the surgical specimen in one case. All the 12 non-small cell lung cancers whose certain diagnosis was adenocarcinoma were positive for TTF-1. TTF-1, CK 5/6 and p63 seem to be useful for differentiating adenocarcinoma from squamous cell carcinoma with 100% specificity, 100% sensitivity and 100% specificity, 97% sensitivity and 87% specificity, and 100% sensitivity, respectively.
  
  
  CONCLUSIONS
  We concluded that TTF-1 is a reliable marker for subtyping lung cancer. Different staining patterns can be seen with CK5/6 and p63; however, if they are used together with TTF-1 and interpreted correctly, they can be of help for the final diagnosis even in cases in which the morphology is unclear.
authors.affiliation: Department of Medical Pathology, İzmir Bozyaka Education and Research Hospital , İZMİR, TURKEY.
authors.forename: Asuman
authors.initials: A
authors.lastname: Argon
authors.forename: Deniz
authors.initials: D
authors.lastname: Nart
authors.forename: Ali
authors.initials: A
authors.lastname: Veral
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000032:analysis*; D053553:Keratin-6 / Q000032:analysis*; D008175:Lung Neoplasms / Q000737:chemistry* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000032:analysis*; D011237:Predictive Value of Tests; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000032:analysis*; D025521:Tumor Suppressor Proteins / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; C503940:KRT5 protein, human; D053555:Keratin-5; D053553:Keratin-6; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; C115051:TP63 protein, human; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins