title: Controversies in using urine samples for Prostate Cancer detection: PSA and PCA3 expression analysis.
abstract: OBJECTIVE
  Prostate cancer (PCa) is one of the most commonly diagnosed malignancies in the world. Although PSA utilization as a serum marker has improved prostate cancer detection it still presents some limitations, mainly regarding its specificity. The expression of this marker, along with the detection of PCA3 mRNA in urine samples, has been suggested as a new approach for PCa detection. The goal of this work was to evaluate the efficacy of the urinary detection of PCA3 mRNA and PSA mRNA without performing the somewhat embarrassing prostate massage. It was also intended to optimize and implement a methodological protocol for this kind of sampling.
  
  
  METHODS
  Urine samples from 57 patients with suspected prostate disease were collected, without undergoing prostate massage. Increased serum PSA levels were confirmed by medical records review. RNA was extracted by different methods and a preamplification step was included in order to improve gene detection by Real-Time PCR.
  
  
  RESULTS
  An increase in RNA concentration with the use of TriPure Isolation Reagent. Despite this optimization, only 15.8% of the cases showed expression of PSA mRNA and only 3.8% of prostate cancer patients presented detectable levels of PCA3 mRNA. The use of a preamplification step revealed no improvement in the results obtained.
  
  
  CONCLUSIONS
  This work confirms that prostate massage is important before urine collection for gene expression analysis. Since PSA and PCA3 are prostate specific, it is necessary to promote the passage of cells from prostate to urinary tract, in order to detect these genetic markers in urine samples.
authors.affiliation: Molecular Oncology Group and Virology LB, Portuguese Institute of Oncology of Porto, Porto, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Fontenete
authors.forename: J
authors.initials: J
authors.lastname: Silva
authors.forename: A L
authors.initials: AL
authors.lastname: Teixeira
authors.forename: R
authors.initials: R
authors.lastname: Ribeiro
authors.forename: E
authors.initials: E
authors.lastname: Bastos
authors.forename: F
authors.initials: F
authors.lastname: Pina
authors.forename: R
authors.initials: R
authors.lastname: Medeiros
mesh_terms: D000368:Aged; D000951:Antigens, Neoplasm / Q000235:genetics / Q000652:urine*; D001706:Biopsy; D051517:Digital Rectal Examination; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D017430:Prostate-Specific Antigen / Q000235:genetics / Q000652:urine*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000652:urine*; D012333:RNA, Messenger / Q000652:urine
chemical_list: D000951:Antigens, Neoplasm; D012333:RNA, Messenger; C479341:prostate cancer antigen 3, human; D017430:Prostate-Specific Antigen