title: Comparison of monoclonal napsin A, polyclonal napsin A, and TTF-1 for determining lung origin in metastatic adenocarcinomas.
abstract: Thyroid transcription factor 1 (TTF-1) is currently the best immunohistochemical marker for carcinomas of lung origin. Our aim was to compare napsin A to TTF-1 for identifying pulmonary origin in metastatic adenocarcinoma and its mimics. One hundred fifty-five metastatic carcinomas (55 pulmonary, 100 nonpulmonary) were stained with monoclonal napsin A and TTF-1, and most also with polyclonal napsin A. The sensitivity of monoclonal napsin A, polyclonal napsin A, and TTF-1 for metastatic adenocarcinomas of pulmonary origin was 76%, 81%, and 82%, respectively. Two lung carcinomas were diffusely positive for monoclonal napsin A, but negative or equivocal for TTF-1. TTF-1 stained 9 of 100 nonpulmonary carcinomas (all thyroid), monoclonal napsin A stained 12 of 100 (4 sites), and polyclonal napsin A stained 27 of 91 (8 sites). Napsin A is expressed in a wider variety of metastatic nonpulmonary carcinomas than TTF-1, and the monoclonal antibody is more specific. Napsin A is a useful adjunct to TTF-1, because occasional lung adenocarcinomas are TTF-1 negative but napsin A positive.
authors.affiliation: Dept of Pathology, State University of New York Upstate Medical University, 750 E Adams St, Syracuse, NY 13210, USA. mukhopas@upstate.edu
authors.forename: Sanjay
authors.initials: S
authors.lastname: Mukhopadhyay
authors.forename: Anna-Luise A
authors.initials: AL
authors.lastname: Katzenstein
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000556:secondary*; D000906:Antibodies; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D014157:Transcription Factors
chemical_list: D000906:Antibodies; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C504003:TTF1 protein, human; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human