title: Cytokeratin 20 as an immunocytochemical marker for detection of urothelial carcinoma in atypical cytology: preliminary retrospective study on archived urine slides.
abstract: Previous studies have shown that expression of cytokeratin 20 (CK20), a constituent of intermediate filaments, is increased in malignant versus benign urine samples. To evaluate whether immunocytochemical staining of CK20 on archived urine slides could be used as a potential adjunct marker for triage of atypical urine cytology, we analyzed a total of 77 archived urine slides obtained from a spectrum of patients with various risks of developing urothelial carcinoma. These patients were divided into four groups on the basis of initial urine cytologic results and subsequent follow-up biopsy findings; group 1 had negative results in both evaluations, whereas the results in group 4 were positive for both cytology and biopsy. Groups 2 and 3 had a diagnosis of atypical urine cytology; however, patients in group 3 had a positive follow-up biopsy, and patients in group 2 did not. The Papanicolaou-stained archived urine slides were destained and then restained immunocytochemically with monoclonal antibody against CK20. With 5% positively stained nonumbrella cells as a threshold, CK20 was positive in 94.4% of group 3 or 4 patients. In contrast, CK20 was positive in 27.3% of group 2 patients and in 10.5% of group 1 patients. The overall sensitivity and specificity for CK20 for the detection of urothelial carcinoma in this population of patients were 94.4% and 80.5%, respectively. This study demonstrated that immunocytochemical analysis of CK20 on archived urine slides could be used to triage atypical urine cytology into low- and high-risk categories and that CK20 might be a simple and useful early detection marker for urothelial carcinoma.
authors.affiliation: Department of Pathology, Jonsson Comprehensive Cancer Center, University of California at Los Angeles Medical Center, 90095, USA.
authors.forename: S
authors.initials: S
authors.lastname: Lin
authors.forename: S L
authors.initials: SL
authors.lastname: Hirschowitz
authors.forename: C
authors.initials: C
authors.lastname: Williams
authors.forename: P
authors.initials: P
authors.lastname: Shintako
authors.forename: J
authors.initials: J
authors.lastname: Said
authors.forename: J Y
authors.initials: JY
authors.lastname: Rao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000652:urine*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007381:Intermediate Filament Proteins / Q000652:urine*; D053554:Keratin-20; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D001749:Urinary Bladder Neoplasms / Q000473:pathology*; D014556:Urine / Q000166:cytology*
chemical_list: D014408:Biomarkers, Tumor; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20