title: Evaluation of napsin A, cytokeratin 5/6, p63, and thyroid transcription factor 1 in adenocarcinoma versus squamous cell carcinoma of the lung.
abstract: BACKGROUND
  The distinction of lung adenocarcinoma from other types of primary lung malignancies is important clinically. Accurate morphologic classification is often hindered because 70% of lung cancers are diagnosed on limited fine-needle aspiration or transbronchial biopsy specimens. Although thyroid transcription factor 1 (TTF-1) has historically been the most specific marker for lung adenocarcinoma, a relatively new marker, napsin A, has recently been shown to be more sensitive and specific than TTF-1.
  
  
  OBJECTIVE
  To find the most cost-effective panel to reliably distinguish lung adenocarcinoma from squamous cell carcinoma.
  
  
  METHODS
  A total of 291 lung cancers were evaluated morphologically (197 adenocarcinomas [75%]; 66 squamous cell carcinomas [25%]; 28 cases could not be classified into either and were dropped). Immunohistochemistry for napsin A, Cytokeratin 5/6, p63, and TTF-1 was performed on a formalin-fixed tissue microarray obtained from Toyama, Japan. Cases were scored as positive or negative against a negative control.
  
  
  RESULTS
  Napsin A had 83% sensitivity and 98% specificity and TTF-1 had 60% sensitivity and 98% specificity for adenocarcinoma. Cytokeratin 5/6 had 53% sensitivity and 96% specificity and p63 had 95% sensitivity and 86% specificity for squamous cell carcinoma. A panel of napsin A and p63 has a specificity of 94% and a sensitivity of 96% for distinguishing adenocarcinoma from squamous cell carcinoma.
  
  
  CONCLUSIONS
  The source of the antibody is important in avoiding false-negative results. The most cost-effective tissue-preserving panel for small biopsy specimens in the differential diagnosis of lung adenocarcinoma versus squamous cell carcinoma is a combination of p63 and napsin A.
authors.affiliation: Department of Pathology, University of Texas Health Science Center, San Antonio, 78229, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Whithaus
authors.forename: Junya
authors.initials: J
authors.lastname: Fukuoka
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Prihoda
authors.forename: Jaishree
authors.initials: J
authors.lastname: Jagirdar
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000378:metabolism; D000328:Adult; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D044963:Biopsy, Fine-Needle; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000378:metabolism; D003362:Cost-Benefit Analysis; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry / Q000191:economics; D053555:Keratin-5 / Q000378:metabolism*; D053553:Keratin-6 / Q000378:metabolism*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: C081876:CKAP4 protein, human; D053555:Keratin-5; D053553:Keratin-6; D008565:Membrane Proteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human