title: Antibody-based detection of ERG rearrangements in prostate core biopsies, including diagnostically challenging cases: ERG staining in prostate core biopsies.
abstract: BACKGROUND
  Fusions of androgen-regulated genes and v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG) occur in approximately 50% of prostate cancers, encoding a truncated ERG product. In prostatectomy specimens, ERG rearrangements are greater than 99% specific for prostate cancer or high-grade prostatic intraepithelial neoplasia adjacent to ERG-rearranged prostate cancer by fluorescence in situ hybridization and immunohistochemistry.
  
  
  OBJECTIVE
  To evaluate ERG staining by immunohistochemistry on needle biopsies, including diagnostically challenging cases.
  
  
  METHODS
  Biopsies from a retrospective cohort (n  =  111) enriched in cores requiring diagnostic immunohistochemistry and a prospective cohort from all cases during 3 months (n  =  311) were stained with an anti-ERG antibody (clone EPR3864).
  
  
  RESULTS
  Among evaluable cores (n  =  418), ERG staining was confined to cancerous epithelium (71 of 160 cores; 44%), high-grade prostatic intraepithelial neoplasia (12 of 68 cores; 18%), and atypical foci (3 of 28 cores; 11%), with staining in only 2 of 162 cores (1%) diagnosed as benign. The ERG was expressed in about 5 morphologically benign glands across 418 cores and was uniformly expressed by all cancerous glands in 70 of 71 cores (99%).
  
  
  CONCLUSIONS
  ERG staining is more prostate cancer-specific than α-methylacyl-coenzyme A racemase, and staining in an atypical focus supports a diagnosis of cancer if high-grade prostatic intraepithelial neoplasia can be excluded. Thus, ERG staining shows utility in diagnostically challenging biopsies and may be useful in molecularly subtyping prostate cancer and in stratifying isolated high-grade prostatic intraepithelial neoplasia by risk of subsequent cancer.
authors: Michigan Center for Translational Pathology, Department of Pathology, University of Michigan Health System, Ann Arbor, MI 48104-5054, USA.
authors: Scott A
authors: SA
authors: Tomlins
authors: Nallasivam
authors: N
authors: Palanisamy
authors: Javed
authors: J
authors: Siddiqui
authors: Arul M
authors: AM
authors: Chinnaiyan
authors: Lakshmi P
authors: LP
authors: Kunju
mesh_terms: D000368:Aged; D000918:Antibody Specificity; D001707:Biopsy, Needle; D015331:Cohort Studies; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D011446:Prospective Studies; D011467:Prostate / Q000378:metabolism* / Q000473:pathology; D019048:Prostatic Intraepithelial Neoplasia / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D000071230:Transcriptional Regulator ERG
chemical_list: C072312:ERG protein, human; D015514:Oncogene Proteins, Fusion; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG