title: Introduction and first clinical application of a simplified immunohistochemical validation system confirms prognostic impact of KI-67 and CK20 for stage T1 urothelial bladder carcinoma: single-center analysis of eight biomarkers in a series of three hundred six patients.
abstract: BACKGROUND
  Biomarkers could help to estimate the prognosis of solid tumors. One of the reasons that many immunohistochemical (IHC) markers are not used routinely is the high interobserver variability and various cutoff values. In the present study, we used a simplified IHC method with a group of 8 biomarkers in stage pT1 urothelial bladder carcinoma (UBC).
  
  
  METHODS
  IHC expression of CK20, KI-67, STK15, MUC7, periostin, fibronectin, survivin, and CXCR4 was assessed independently by 2 reviewers in a series of 306 stage pT1 UBC specimens from a single center in 10% steps from < 10% up to > 90%. A general center < 10% vs. ≥ 10% was set for further analysis for all markers. All patients initially underwent a bladder-sparing approach. Kaplan-Meier analyses and multivariate Cox regression analyses of recurrence-free survival (RFS), progression-free survival (PFS), and cancer-specific survival (CSS) were performed.
  
  
  RESULTS
  A cutoff point ≥ 10% was shown to be valid and reliable for marker expression, with 96% interobserver agreement. Of the studied marker expressions, ≥ 10% for Ki-67 showed a statistically significant worse RFS (54% vs. 64%; P = .004), PFS (66% vs. 73%; P = .001), and CSS (71% vs. 77%; P = .015); ≥ 10% for CK20 showed a worse RFS (57% vs. 58%; P = .009). Multivariate Cox regression analysis revealed CK20 to be an independent prognostic factor for recurrence (hazard ratio [HR], 2.08; confidence interval [95% CI]; 1.21-3.57; P = .008) and Ki-67 for progression (HR, 2.11; CI, 1.02-4.37; P = .045).
  
  
  CONCLUSIONS
  We proposed and applied a simplified IHC evaluation that increases interobserver agreement and confirms the prognostic role of Ki-67 and CK20 for stage T1 UBC.
authors.affiliation: St. Josef Medical Centre, Department of Urology of Regensburg University, Regensburg, Germany. Electronic address: wolfgang.otto@klinik.uni-regensburg.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Otto
authors.forename: Stefan
authors.initials: S
authors.lastname: Denzinger
authors.forename: Hans-Martin
authors.initials: HM
authors.lastname: Fritsche
authors.forename: Maximilian
authors.initials: M
authors.lastname: Burger
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rößler
authors.forename: Simone
authors.initials: S
authors.lastname: Bertz
authors.forename: Matthias
authors.initials: M
authors.lastname: May
authors.forename: Arndt
authors.initials: A
authors.lastname: Hartmann
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Hofstädter
authors.forename: Wolf F
authors.initials: WF
authors.lastname: Wieland
authors.forename: Fabian
authors.initials: F
authors.lastname: Eder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D053554:Keratin-20 / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D013534:Survival; D001743:Urinary Bladder / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis*; D019459:Urothelium / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; C507499:KRT20 protein, human; D053554:Keratin-20; D019394:Ki-67 Antigen
keywords: Biomarkers; Early invasive bladder cancer; Immunohistochemistry; Prognosis; Urothelial bladder carcinoma