title: Utility of cytokeratin immunostaining in separating pulmonary adenocarcinomas from colonic adenocarcinomas.
abstract: Adenocarcinomas of uncertain origin are a frequent problem for surgical pathologists. To determine the utility of immunostaining for cytokeratin 7 and cytokeratin 20 in the separation of pulmonary adenocarcinomas from colonic adenocarcinomas, we studied routinely processed, formalin-fixed tissue from 151 of these tumors using commercially available monoclonal antibodies and an avidin-biotin immunohistochemical technique. Used alone, neither cytokeratin 7 immunostaining or cytokeratin 20 immunostaining reliably separated these tumors. However, the immunophenotype of cytokeratin 7 positive/cytokeratin 20 negative was seen in 86% of the pulmonary adenocarcinomas, and in 0% of the colonic adenocarcinomas. Conversely, the cytokeratin 7-negative/cytokeratin 20-positive immunophenotype was seen in 77% of the colonic carcinomas, and in 0% of the pulmonary tumors. In conclusion, cytokeratin 7/cytokeratin 20 immunostaining patterns may be helpful in separating pulmonary adenocarcinomas from colonic adenocarcinomas.
authors.affiliation: Department of Pathology, University of Missouri Medical Center, Columbia 65212.
authors.forename: T S
authors.initials: TS
authors.lastname: Loy
authors.forename: R D
authors.initials: RD
authors.lastname: Calaluce
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000175:diagnosis / Q000556:secondary; D003110:Colonic Neoplasms / Q000737:chemistry* / Q000175:diagnosis; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis*; D053554:Keratin-20; D007633:Keratins / Q000032:analysis*; D008175:Lung Neoplasms / Q000737:chemistry* / Q000175:diagnosis
chemical_list: D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20; D007633:Keratins