APTIMA PCA3 molecular urine test: development of a method to aid in the diagnosis of prostate cancer

Clin Chem. 2006 Jun;52(6):1089-95. doi: 10.1373/clinchem.2005.063289. Epub 2006 Apr 20.

Abstract

Background: Prostate cancer gene 3 (PCA3) encodes a prostate-specific mRNA that has shown promise as a prostate cancer diagnostic tool. This report describes the characterization of a prototype quantitative PCA3-based test for whole urine.

Methods: Whole-urine specimens were collected after digital rectal examination from 3 groups: men scheduled for prostate biopsy (n = 70), healthy men (<45 years of age with no known prostate cancer risk factors; n = 52), and men who had undergone radical prostatectomy (n = 21). PCA3 and prostate-specific antigen (PSA) mRNAs were isolated, amplified, and quantified by use of Gen-Probe DTS400 Systems. Prostate biopsy results were correlated with the PCA3/PSA mRNA ratio, and PSA mRNA concentrations were used to normalize PCA3 signals and confirm the yield of prostate-specific RNA. Assay precision, specimen stability, and mRNA yield were also evaluated.

Results: The specimen informative rate (fraction of specimens yielding sufficient RNA for analysis) was 98.2%. In this clinical research study, ROC curve analysis of prebiopsy specimens yielded an area under the curve of 0.746; sensitivity was 69% and specificity 79%. Serum PSA assay specificity was 28% for this same group. PCA3 and PSA mRNAs were undetectable in postprostatectomy specimens except for one man with recurrent prostate cancer. Assay interrun CVs were < or =12%. Both mRNAs were stable in processed urine up to 5 days at 4 degrees C and after 5 freeze-thaw cycles.

Conclusion: The APTIMA PCA3 assay combines simple specimen processing with precise assays and existing instruments and could add specificity to the current algorithm for prostate cancer diagnosis.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Antigens, Neoplasm / genetics*
  • Antigens, Neoplasm / urine*
  • Humans
  • Male
  • Middle Aged
  • Prostate-Specific Antigen / genetics
  • Prostate-Specific Antigen / urine
  • Prostatic Neoplasms / diagnosis*
  • RNA Stability
  • RNA, Messenger / urine
  • ROC Curve
  • Sensitivity and Specificity
  • Specimen Handling

Substances

  • Antigens, Neoplasm
  • RNA, Messenger
  • prostate cancer antigen 3, human
  • Prostate-Specific Antigen