title: Immunocytochemical detection of ERG expression in exfoliated urinary cells identifies with high specificity patients with prostate cancer.
abstract: OBJECTIVE
  To evaluate the immunocytochemical detection of ERG protein in exfoliated cells as a means of identifying patients with prostate cancer (PCa) before prostate biopsy.
  
  
  METHODS
  Urine samples (30 mL) were collected after digital rectal examination (DRE) from 159 patients with an elevated age-specific prostate-specific antigen (PSA) and/or an abnormal DRE who underwent prostate biopsy. In all cases, exfoliated urinary cells from half of the urine sample underwent immunocytochemical assessment for ERG protein expression. Exfoliated cells in the remaining half underwent assessment of TMPRSS2:ERG status using either nested reverse-transcriptase (RT)-PCR (151 cases) or fluorescence in situ hybridization (FISH; eight cases). Corresponding tissue samples were evaluated using FISH to determine chromosomal gene fusion tissue status and immunohistochemistry (IHC) to determine ERG protein expression. Results were correlated with clinicopathological variables.
  
  
  RESULTS
  The sensitivity and specificity of urinary ERG immunocytochemistry (ICC) for PCa were 22.7 and 100%, respectively. ERG ICC results correlated with advanced tumour grade, stage and higher serum PSA. In comparison, urine TMPRSS2:ERG transcript analysis had 27% sensitivity and 98% specificity for PCa detection. On tissue IHC, ERG staining was highly specific for PCa. In all, 52% of cancers harboured foci of ERG staining; however, only 46% of cancers that were found to have ERG overexpression were positive on urine ICC. The ERG ICC results showed strong concordance with urinary RT-PCR and FISH, and tissue IHC and FISH.
  
  
  CONCLUSIONS
  This is the first study to show that cytological gene fusion detection using ICC is feasible and identifies patients with adverse disease markers. ERG ICC was highly specific, but this technique was less sensitive than RT-PCR.
authors.affiliation: Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, UK.|Department of Urology, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Raj P
authors.initials: RP
authors.lastname: Pal
authors.affiliation: Department of Urology, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Roger C
authors.initials: RC
authors.lastname: Kockelbergh
authors.affiliation: Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, UK.
authors.forename: John Howard
authors.initials: JH
authors.lastname: Pringle
authors.affiliation: Department of Cytogenetics, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Lara
authors.initials: L
authors.lastname: Cresswell
authors.affiliation: Department of Cellular Pathology, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Roger
authors.initials: R
authors.lastname: Hew
authors.affiliation: Department of Cellular Pathology, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: John P
authors.initials: JP
authors.lastname: Dormer
authors.affiliation: Department of Cancer Genetics, University of East Anglia, Norwich, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Cooper
authors.affiliation: Department of Urology, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: John Kilian
authors.initials: JK
authors.lastname: Mellon
authors.affiliation: Department of Genetics, University of Leicester, Leicester, UK.
authors.forename: Julian G
authors.initials: JG
authors.lastname: Barwell
authors.affiliation: Department of Genetics, University of Leicester, Leicester, UK.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Hollox
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D062005:Biopsy, Large-Core Needle; D055088:Early Detection of Cancer; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology* / Q000652:urine; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D000071230:Transcriptional Regulator ERG
chemical_list: C072312:ERG protein, human; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D012697:Serine Endopeptidases; C421305:TMPRSS2 protein, human; D017430:Prostate-Specific Antigen
keywords: ERG; gene fusions; prostate cancer; protein; urine