title: Large cell carcinoma of the lung: an endangered species?
abstract: This study aims to evaluate large cell carcinomas (LCC) of the lung with a panel of immunohistochemical markers in an attempt to identify tumors belonging to other categories. We analyzed a tissue microarray platform of 101 LCC with a panel of 31 monoclonal antibodies. The tumors were 82 (81.3%) classic LCC, 7 (6.9%) neuroendocrine LCC, 6 (5.9%) lymphoepithelioma-like LCC, 3 (2.9%) basaloid LCC, 2 (2%) clear cell LCC, and 1 (1%) LCC with rhabdoid phenotype. Characteristic classic LCC immunophenotype was loss of staining with CK5/6, CK14 positive in most squamous cell carcinoma (SCC), lack of MOC 31 positive in most adenocarcinomas, and positive immunoreactivity to EGFR, PDGFR-alpha and c-kit. 27 of 82 classic LCC (32.9%) were re-classified as adenocarcinomas, because they coexpressed TTF-1, CK7, and CK19, and were negative for p63. 31 (37.8%) of 82 classic LCC were reclassified as poorly differentiated SCC, based on their immunoreactivity with 34betaE12, p63, thrombomodulin, and CD44v6. 16 (19.5%) of 82 classic LCC correspond to undifferentiated adenosquamous carcinomas, since they displayed conflicting immunostaining for markers of both SCC and adenocarcinomas. The use of 7 immunohistochemical markers, consisting of TTF-1, CK7, CK19, p63, 34betaE12, thrombomodulin, and CD44v6, markedly reduces dramatically to less than 10%, the number of classic LCC by readily identifying cases of poorly differentiated SCCs, adenosquamous carcinoma and adenocarcinomas.
authors.affiliation: Department of Pathology, Clinica Universitaria, University of Navarra, Navarra, Spain. jpardo@unav.es
authors.forename: Javier
authors.initials: J
authors.lastname: Pardo
authors.forename: Ana M
authors.initials: AM
authors.lastname: Martinez-Peñuela
authors.forename: Jesús J
authors.initials: JJ
authors.lastname: Sola
authors.forename: Angel
authors.initials: A
authors.lastname: Panizo
authors.forename: Alfonso
authors.initials: A
authors.lastname: Gúrpide
authors.forename: Jose M
authors.initials: JM
authors.lastname: Martinez-Peñuela
authors.forename: Maria D
authors.initials: MD
authors.lastname: Lozano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000276:immunology; D018287:Carcinoma, Large Cell / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008175:Lung Neoplasms / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
chemical_list: D000911:Antibodies, Monoclonal