title: ERG immunohistochemistry and clinicopathologic characteristics in Korean prostate adenocarcinoma patients.
abstract: BACKGROUND
  Transmembrane protease serine 2-ETS related gene (TMPRSS2-ERG) gene fusion, the most common genetic alternation in prostate cancer, is associated with protein expression of the oncogene ERG. Recently, an immunohistochemical staining method using an anti-ERG antibody was shown to have a strong correlation with altered ERG protein expression.
  
  
  METHODS
  We analyzed a total of 303 radical prostatectomy specimens (obtained from Korean prostate cancer cases) using a constructed tissue microarray and ERG immunohistochemical staining. Thereafter, we evaluated the association between ERG expression and clinicopathological factors.
  
  
  RESULTS
  The ERG-positive rate was 24.4% (74/303) and significantly higher ERG expression was observed in the subgroup with a lower Gleason score (p=0.004). Analysis of the histologic pattern of prostate adenocarcinomas revealed that tumors with discrete glandular units (Gleason pattern 3) displayed higher frequency of ERG expression (p=0.016). The ERG-positive rate was lower than that found (approximately 50%) in studies involving western populations. Other factors including age, tumor volume, initial protein-specific antigen level, a pathological stage and margin status were not significantly related with the ERG expression.
  
  
  CONCLUSIONS
  ERG immunohistochemical staining is significantly higher in tumors with well-formed glands and is associated with a lower Gleason score.
authors.affiliation: Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ja Hee
authors.initials: JH
authors.lastname: Suh
authors.forename: Jeong-Whan
authors.initials: JW
authors.lastname: Park
authors.forename: Cheol
authors.initials: C
authors.lastname: Lee
authors.forename: Kyung Chul
authors.initials: KC
authors.lastname: Moon
keywords: ERG; Immunohistochemistry; Prostate neoplasms