title: Evaluation of napsin A, TTF-1, p63, p40, and CK5/6 immunohistochemical stains in pulmonary neuroendocrine tumors.
abstract: OBJECTIVE
  A panel of immunohistochemical (IHC) stains frequently used to subclassify non-small cell lung cancers (NSCLCs) includes napsin A, TTF-1, CK5/6, p40, and p63. The expression profiles of these stains in neuroendocrine tumors have not been systematically evaluated.
  
  
  METHODS
  Sixty-eight resected pulmonary neuroendocrine tumors, including 52 typical carcinoids (TCs), eight atypical carcinoids (ACs), seven small cell carcinomas (SCLCs) and one large cell neuroendocrine carcinoma (LCNEC), were stained for napsin A, TTF-1, p63, p40, and CK5/6. Tumors were scored as positive (>1% tumor cells reactive) or negative, and percentage of reactive tumor cells was recorded.
  
  
  RESULTS
  Napsin A, p63, p40, and CK5/6 were consistently negative in neuroendocrine tumors. TTF-1 was positive in 17 of 52 TCs, 4 of 8 ACs, 5 of 7 SCLCs, and 0 of 1 LCNECs.
  
  
  CONCLUSIONS
  Pulmonary neuroendocrine tumors have a distinct but nonspecific profile on IHC panel commonly applied to subclassify NSCLCs. They are napsin A-/p40-/p63-/CK5/6-/TTF-1±. Recognizing this profile may have value in separating neuroendocrine tumors from NSCLCs.
authors.affiliation: From the Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis;
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor; and.
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Schmidt
authors.affiliation: Department of Molecular and Cellular Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Hatanaka
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor; and.
authors.forename: Dafydd
authors.initials: D
authors.lastname: Thomas
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor; and.
authors.forename: Amir
authors.initials: A
authors.lastname: Lagstein
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor; and.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Myers
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D016056:Immunodominant Epitopes / Q000378:metabolism; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000378:metabolism; D053553:Keratin-6 / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D008565:Membrane Proteins / Q000378:metabolism; D018358:Neuroendocrine Tumors / Q000378:metabolism* / Q000473:pathology; D010446:Peptide Fragments / Q000378:metabolism; D014157:Transcription Factors
chemical_list: D014408:Biomarkers, Tumor; C081876:CKAP4 protein, human; D004268:DNA-Binding Proteins; D016056:Immunodominant Epitopes; D053555:Keratin-5; D053553:Keratin-6; D008565:Membrane Proteins; C495942:P40, iodinated C-terminal peptide, human; D010446:Peptide Fragments; C504003:TTF1 protein, human; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human
keywords: Carcinoid; Immunohistochemistry; Napsin A; Pulmonary neuroendocrine tumor