PSA Isoforms: [−2]proPSA Significant Adjunct to Free PSA

  • Jeffrey E. Tam
Chapter
Part of the Current Clinical Urology book series (CCU)

Summary

Prostate-Specific Antigen (PSA) is a widely used serum marker to aid in the diagnosis of prostate cancer and monitor its treatment. PSA by itself has limited specificity, and cannot distinguish between early stage prostate cancer and benign prostatic hyperplasia (BPH), resulting in many unnecessary biopsies. The specificity of PSA for prostate cancer was improved when it was discovered that complex and free forms of PSA existed in serum and the ratio of free to complexed PSA (%free PSA) correlated to prostate cancer. It is now known that the free form of PSA is actually composed of several proenzyme forms and enzymatically nicked PSA. The major nicked form is common to benign hyperplasia and is referred to as Benign PSA (BPSA). The proenzyme forms of PSA are collectively called proPSA and are associated with prostate cancer. There are three recognized proPSA isoforms ([−5/−7]proPSA, [−4]proPSA, and [−2]proPSA) that increase the utility of PSA in prostate cancer diagnosis.

Key Words

Prostate Cancer PSA proPSA Immunoassay Diagnosis Markers 
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Copyright information

© Humana Press, a part of Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Jeffrey E. Tam
    • 1
  1. 1.Beckman Coulter Inc.ChaskaUSA

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