title: Molecular assays for the detection of prostate tumor derived nucleic acids in peripheral blood.
abstract: BACKGROUND
  Prostate cancer is the second leading cause of cancer mortality in American men. Although serum PSA testing is widely used for early detection, more specific prognostic tests are needed to guide treatment decisions. Recently, the enumeration of circulating prostate epithelial cells has been shown to correlate with disease recurrence and metastasis following definitive treatment. The purpose of our study was to investigate an immunomagnetic fractionation procedure to enrich circulating prostate tumor cells (CTCs) from peripheral blood specimens, and to apply amplified molecular assays for the detection of prostate-specific markers (PSA, PCA3 and TMPRSS2:ERG gene fusion mRNAs).
  
  
  RESULTS
  As few as five prostate cancer cells were detected per 5 mL of whole blood in model system experiments using anti-EpCAM magnetic particles alone or in combination with anti-PSMA magnetic particles. In our experiments, anti-EpCAM magnetic particles alone exhibited equivalent or better analytical performance with patient samples compared to a combination of anti-EpCAM + anti-PSMA magnetic particles. Up to 39% of men with advanced prostate cancer tested positive with one or more of the molecular assays tested, whereas control samples from men with benign prostate hyperplasia gave consistently negative results as expected. Interestingly, for the vast majority of men who tested positive for PSA mRNA following CTC enrichment, their matched plasma samples also tested positive, although CTC enrichment gave higher overall mRNA copy numbers.
  
  
  CONCLUSIONS
  CTCs were successfully enriched and detected in men with advanced prostate cancer using an immunomagnetic enrichment procedure coupled with amplified molecular assays for PSA, PCA3, and TMPRSS2:ERG gene fusion mRNAs. Our results indicate that men who test positive following CTC enrichment also exhibit higher detectable levels of non-cellular, circulating prostate-specific mRNAs.
authors.affiliation: Gen-Probe Incorporated, San Diego, CA 92121, USA.
authors.forename: Matthias
authors.initials: M
authors.lastname: Jost
authors.forename: John R
authors.initials: JR
authors.lastname: Day
authors.forename: Ryan
authors.initials: R
authors.lastname: Slaughter
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Koreckij
authors.forename: Deanna
authors.initials: D
authors.lastname: Gonzales
authors.forename: Martin
authors.initials: M
authors.lastname: Kinnunen
authors.forename: Jack
authors.initials: J
authors.lastname: Groskopf
authors.forename: Harry G
authors.initials: HG
authors.lastname: Rittenhouse
authors.forename: Robert L
authors.initials: RL
authors.lastname: Vessella
authors.forename: Mark A
authors.initials: MA
authors.lastname: Reynolds
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D018189:Immunomagnetic Separation; D008297:Male; D009696:Nucleic Acids / Q000097:blood* / Q000235:genetics; D017430:Prostate-Specific Antigen / Q000235:genetics; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology
chemical_list: D009696:Nucleic Acids; D017430:Prostate-Specific Antigen