title: Cytokeratin expression patterns in low-grade papillary urothelial neoplasms of the urinary bladder.
abstract: BACKGROUND
  The differential expression patterns of cytokeratin 20 (CK20) and 34betaE12 antigen in low-grade papillary urothelial tumors of the bladder are discussed.
  
  
  METHODS
  A retrospective study of 120 patients with low-grade papillary bladder tumors (45 neoplasms of low malignant potential and 75 low-grade WHO G1 carcinomas) was performed. All tumors were graded in accordance with the 1998 World Health Organization/International Society of Urological Pathology (WHO/ISUP) and 1999 WHO classifications. The mean follow-up was 76.6 months (range, 36-168 mos), considering for prognostic purposes the time to first recurrence, or relapse-free interval (RFI), and the total number of recurrent patients. Immunohistochemically, normal or abnormal CK20 and 34betaE12 antigen expression patterns were determined for each patient. CK20 (clone IT-Ks) and a high-molecular weight cytokeratin (clone 34betaE12) were the monoclonal antibodies used in the immunohistochemical study.
  
  
  RESULTS
  Seventy-seven of 120 patients (64.2%) experienced a recurrence during follow-up. In recurrence prediction, the differential expression pattern of both cytokeratins showed a high sensitivity (76.6% for CK20 and 80.5% for 34betaE12 antigen) and a high positive predictive value (85.5% for CK20 and 75.6% for 34betaE12 antigen), although specificity was higher for CK20 (76.7%) than it was for 34betaE12 antigen (53.4%). Independent of adjuvant intravesical chemotherapy, these 2 markers showed a strong statistical correlation (p < 0.001) in univariate studies with both the prediction of disease recurrences and RFI.
  
  
  CONCLUSIONS
  CK20 and 34betaE12 antigen have proved to be strong predictive markers of disease recurrences when considering different topographic expression profiles, and, in the authors' opinion, these profiles could be incorporated into follow-up clinicopathologic strategies.
authors.affiliation: Department of Pathology, University of Valencia Medical School, Valencia, Spain. david.ramos@uv.es
authors.forename: David
authors.initials: D
authors.lastname: Ramos
authors.forename: Samuel
authors.initials: S
authors.lastname: Navarro
authors.forename: Rafael
authors.initials: R
authors.lastname: Villamón
authors.forename: Manuel
authors.initials: M
authors.lastname: Gil-Salom
authors.forename: Antonio
authors.initials: A
authors.lastname: Llombart-Bosch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002291:Carcinoma, Papillary / Q000378:metabolism* / Q000473:pathology; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D053554:Keratin-20; D007633:Keratins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000378:metabolism; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D001749:Urinary Bladder Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C121278:CK-34 beta E12; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20; D007633:Keratins