Prostate-Specific Antigen and Early Detection of Prostate Cancer

Abstract

Prostate-specific antigen (PSA) is biochemically a 33-kDa serine protease and is the prototype of tumor marker most useful in investigating basic science and clinical application of prostate cancer. As an immunohistopathological marker, PSA is especially effective in the identification of distant metastatic prostate carcinoma and in the differential diagnosis of poorly differentiated transitional cell carcinomas of the bladder from prostate carcinoma. As a serologic marker, PSA is most useful in staging, monitoring and in early detection of recurrent disease. The greatest value of PSA is as a screening aid along with digital rectal examination for early detection of prostate cancer. PSA-based screening tests have been performed in various regions of the world and have yielded prostate cancer detection rates proportional to that of incidence rates in the countries. Most significantly, PSA detects early nonpalpable prostate cancer. Approximately 85% of the prostate tumors detected through PSA have the clinical features associated with medically important cancer. Further, a majority of the tumors, 70%, are confined to the organ. Although the issues of cost-benefit and increase in ultimate survival rate are still being evaluated in two large-scale randomized national trials, timely and definitive therapies of these potentially lethal tumors can result in high cure rate and improve the quality of patients’ life.

Immunofluorometric assay of human kallikrein 6 (zyme/protease M/neurosin) and preliminary clinical applications

“…To examine these possibilities, highly sensitive and specific immunologic procedures need to be developed. The experience with prostate specific antigen has indicated that only when specific and sensitive immunoassays became available, PSA testing has gained widespread use (4). In this paper, we describe development of polyclonal antibodies and an immunofluorometric procedure suitable for quantifying hK6 protein in biologic fluids and tissue extracts.…”

“…This gene family has contributed two excellent biomarkers (PSA and hK2) that are currently used for diagnosis and monitoring of prostate cancer (1)(2)(3)(4)(5)(6).…”

“…This gene family now contains 14 genes that are all encoding for serine proteases, show significant homologies at both the DNA and the amino acid level, and are all localized in tandem on human chromosome 19q13.3-q13. 4. Recent developments on this gene family have been reviewed (1).…”

The Spectrum of Human Kallikrein 6 (Zyme/Protease M/Neurosin) Expression in Human Tissues as Assessed by Immunohistochemistry

“…The latter two kallikreins, PSA and hK2, are relatively prostate-specific and have already found important applications as biomarkers for the diagnosis and monitoring of prostate cancer (Chu 1997;Rittenhouse et al 1998;Diamandis 1999;McCormack et al 1995;Stenman 1999;Diamandis et al 2000a).…”

Role of Ca 15-3 in patients with biochemically suspected prostate cancer and multiple negative ultrasound-guided prostate biopsies

“…5 Other benign diseases (urine retention, prostatitis, prostatic infarction) and simple procedures (digital-rectal examination (DRE), transrectal ultrasound (TRUS) and prostate biopsy) can raise serum PSA concentrations. 6,7 Because of the above-mentioned limitations of serum PSA determinations, the use of alternative easily detectable low-cost serum markers has become mandatory in diagnosing early cancer in cases where clinically, instrumentally and biochemically suspected cancer is not supported by histologic findings.…”