title: Cytokeratin 7 and 20 staining for the diagnosis of lung and colorectal adenocarcinoma.
abstract: The origin of metastatic adenocarcinoma lesions can sometimes be difficult to diagnose. The objectives of our study were to establish the cytokeratin staining pattern of primary and metastatic lung and colorectal adenocarcinomas, and to determine if this helps to identify the site of origin of metastatic lesions. We reviewed a total of 102 tissue samples from patients in our tumour registry, with either primary or metastatic lung or colorectal adenocarcinoma. Tissue sections were stained for cytokeratin 7 and 20 and read as positive or negative for staining. Clinical and radiologic information was reviewed from computerised charts. The cytokeratin 7+/cytokeratin 20- pattern characterised 96% (29 out of 30) of primary and 95% (21 out of 22) of metastatic lung adenocarcinomas. All the primary (26), and 88% (21 out of 24) of metastatic colorectal adenocarcinomas stained cytokeratin 7-/cytokeratin 20+. Samples from a variety of metastatic sites were evaluated for cytokeratin 7 and 20 staining. Out of the 102 samples, in 95% (97 out of 102) of the cases, the cytokeratin 7 and cytokeratin 20 staining pattern characterised and differentiated between lung and colorectal adenocarcinoma. Primary and metastatic lung adenocarcinomas show a cytokeratin 7+/cytokeratin 20- staining pattern, while colorectal adenocarcinomas stain cytokeratin 7-/cytokeratin 20+. Cytokeratin staining is helpful in the diagnostic differentiation of metastatic lesions from these two common primaries, and assists in determining the site of origin of metastatic lesions.
authors.affiliation: Department of Medicine, Yale Cancer Center, Yale University School of Medicine and VA Connecticut Cancer Center, VA Connecticut Healthcare System, 950 Campbell Avenue, 111D, West Haven, Connecticut, CT 06516, USA. kummars@yahoo.com
authors.forename: S
authors.initials: S
authors.lastname: Kummar
authors.forename: M
authors.initials: M
authors.lastname: Fogarasi
authors.forename: A
authors.initials: A
authors.lastname: Canova
authors.forename: A
authors.initials: A
authors.lastname: Mota
authors.forename: T
authors.initials: T
authors.lastname: Ciesielski
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D001706:Biopsy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D007124:Immunoenzyme Techniques; D007381:Intermediate Filament Proteins / Q000378:metabolism; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000378:metabolism; D008175:Lung Neoplasms / Q000175:diagnosis*; D011379:Prognosis; D012042:Registries; D013194:Staining and Labeling / Q000379:methods
chemical_list: D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins