title: Novel RNA hybridization method for the in situ detection of ETV1, ETV4, and ETV5 gene fusions in prostate cancer.
abstract: The genetic basis of 50% to 60% of prostate cancer (PCa) is attributable to rearrangements in E26 transformation-specific (ETS) (ERG, ETV1, ETV4, and ETV5), BRAF, and RAF1 genes and overexpression of SPINK1. The development and validation of reliable detection methods are warranted to classify various molecular subtypes of PCa for diagnostic and prognostic purposes. ETS gene rearrangements are typically detected by fluorescence in situ hybridization and reverse-transcription polymerase chain reaction methods. Recently, monoclonal antibodies against ERG have been developed that detect the truncated ERG protein in immunohistochemical assays where staining levels are strongly correlated with ERG rearrangement status by fluorescence in situ hybridization. However, specific antibodies for ETV1, ETV4, and ETV5 are unavailable, challenging their clinical use. We developed a novel RNA in situ hybridization-based assay for the in situ detection of ETV1, ETV4, and ETV5 in formalin-fixed paraffin-embedded tissues from prostate needle biopsies, prostatectomy, and metastatic PCa specimens using RNA probes. Further, with combined RNA in situ hybridization and immunohistochemistry we identified a rare subset of PCa with dual ETS gene rearrangements in collisions of independent tumor foci. The high specificity and sensitivity of RNA in situ hybridization provides an alternate method enabling bright-field in situ detection of ETS gene aberrations in routine clinically available PCa specimens.
authors.affiliation: *Michigan Center for Translational Pathology Departments of †Pathology §Urology ‡Comprehensive Cancer Center ∥Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI.
authors.forename: Lakshmi P
authors.initials: LP
authors.lastname: Kunju
authors.forename: Shannon
authors.initials: S
authors.lastname: Carskadon
authors.forename: Javed
authors.initials: J
authors.lastname: Siddiqui
authors.forename: Scott A
authors.initials: SA
authors.lastname: Tomlins
authors.forename: Arul M
authors.initials: AM
authors.lastname: Chinnaiyan
authors.forename: Nallasivam
authors.initials: N
authors.lastname: Palanisamy
mesh_terms: D017500:Adenovirus E1A Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D050939:Gene Fusion; D006801:Humans; D008297:Male; D009693:Nucleic Acid Hybridization / Q000379:methods; D011471:Prostatic Neoplasms / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D050783:Proto-Oncogene Proteins c-ets; D012334:RNA, Neoplasm / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D017500:Adenovirus E1A Proteins; D004268:DNA-Binding Proteins; C095239:ETV1 protein, human; C079853:ETV4 protein, human; C086680:ETV5 protein, human; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D012334:RNA, Neoplasm; D014157:Transcription Factors