title: Combination of napsin A and TTF-1 immunohistochemistry helps in differentiating primary lung adenocarcinoma from metastatic carcinoma in the lung.
abstract: Differentiation of primary from metastatic adenocarcinoma in the lung can be challenging, and it demands sensitive and specific biomarkers, especially when the tissue for diagnosis is limited. Thyroid transcription factor-1 (TTF-1) has been considered a reliable marker for adenocarcinoma of lung origin. However, several recent studies have shown that TTF-1 immunostaining is also positive in adenocarcinomas arising in different organs including colon, endometrium, endocervix, and ovary. In addition, approximately 20% of lung primary adenocarcinomas are negative for TTF-1 immunostaining, and napsin A immunostaining has slightly higher sensitivity in detecting lung primary adenocarcinoma. We performed TTF-1 and napsin A immunostaining on 120 cases of primary lung adenocarcinomas and 37 cases of metastatic carcinomas in the lung. The results showed that 95 (79.2%) of 120 lung primary adenocarcinomas showed napsin A+/TTF-1+ double-positive immunostaining pattern. TTF-1⁻/napsin A+, TTF-1+/napsin A⁻, and TTF-1⁻/napsin A⁻ were seen in 8.3%, 3.3%, and 9.2% lung primary adenocarcinomas, respectively. Eight (21.6%) of the 37 metastatic carcinomas were positive for TTF-1 and they include clear-cell renal cell carcinomas completely negative for napsin A although napsin A was detected in 12 (80.0%) of 15 primary papillary and 3 (33.3%) of 9 primary clear-cell renal cell carcinomas. All renal epithelial neoplasms were TTF-1 negative. These findings indicate that double napsin A and TTF-1-positive immunostaining is highly specific for lung primary adenocarcinoma and the combination of these 2 biomarkers is warranted to help segregating primary lung adenocarcinoma from metastatic carcinoma in the lung.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors.forename: Jiqing
authors.initials: J
authors.lastname: Ye
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Findeis-Hosey
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.forename: Loralee A
authors.initials: LA
authors.lastname: McMahon
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Yao
authors.forename: Faqian
authors.initials: F
authors.lastname: Li
authors.forename: Haodong
authors.initials: H
authors.lastname: Xu
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D009687:Nuclear Proteins / Q000378:metabolism*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human