scholarly journals Development of Sensitive Immunoassays for Free and Total Human Glandular Kallikrein 2

2004 ◽  
Vol 50 (9) ◽  
pp. 1607-1617 ◽  
Author(s):  
Ville Väisänen ◽  
Susann Eriksson ◽  
Kaisa K Ivaska ◽  
Hans Lilja ◽  
Martti Nurmi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Detection Limit ◽  
Solid Phase ◽  
Specific Antigen ◽  
Control Group ◽  
Serum Samples ◽  
Human Kallikrein 2 ◽  
Kallikrein 2 ◽  
Capture Antibody ◽  
Total Psa

Abstract Background: Free and total human kallikrein 2 (hK2) might improve the discrimination between prostate cancer and benign prostatic hyperplasia. Concentrations of hK2 are 100-fold lower than concentrations of prostate-specific antigen (PSA); therefore, an hK2 assay must have a low detection limit and good specificity. Methods: PSA- and hK2-specific monoclonal antibodies were used in solid-phase, two-site immunofluorometric assays to detect free and total hK2. The total hK2 assay used PSA-specific antibodies to block nonspecific signal. The capture antibody of the free hK2 assay did not cross-react with PSA. To determine the hK2 concentrations in the male bloodstream, total hK2 was measured in a control group consisting of 426 noncharacterized serum samples. Free and total hK2 were measured in plasma from 103 patients with confirmed prostate cancer. Results: All 426 males in the control group had a total hK2 concentration above the detection limit of 0.0008 μg/L. The median total hK2 concentration was 0.022 μg/L (range, 0.0015–0.37 μg/L). hK2 concentrations were 0.1–58% of total PSA (median, 3.6%). hK2 concentrations were similar in men 41–50 and 51–60 years of age. The ratio of hK2 to PSA steadily decreased from 5–30% at PSA <1 μg/L to 1–2% at higher PSA concentrations. In 103 patients with prostate cancer, the median hK2 concentration in plasma was 0.079 μg/L (range, 0.0015–16.2 μg/L). The median free hK2 concentration was 0.070 (range, 0.005–12.2) μg/L. The proportion of free to total hK2 varied from 17% to 131% (mean, 85%). Conclusions: The wide variation in the free-to-total hK2 ratio suggests that hK2 in blood plasma is not consistently in the free, noncomplexed form in patients with prostate cancer. The new assay is sufficiently sensitive to be used to study the diagnostic accuracies of free and total hK2 for prostate cancer.

scholarly journals Dual-Label Immunoassay for Simultaneous Measurement of Prostate-specific Antigen (PSA)-α1-Antichymotrypsin Complex Together with Free or Total PSA

2003 ◽  
Vol 49 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Lei Zhu ◽  
Jari Leinonen ◽  
Wan-Ming Zhang ◽  
Patrik Finne ◽  
Ulf-Håkan Stenman
Keyword(s):  
Detection Limit ◽  
Prostate Specific Antigen ◽  
Simultaneous Measurement ◽  
Solid Phase ◽  
Specific Antigen ◽  
Cathepsin G ◽  
Serum Samples ◽  
Total Psa ◽  
Dual Label

Abstract Background: A major portion of prostate-specific antigen exists in circulation as a complex with α1-antichymotrypsin (PSA-ACT), whereas a minor part is free (fPSA). The proportion of PSA-ACT is increased in prostate cancer (PCa), but immunologic determination of PSA-ACT is hampered by a background produced by nonspecific adsorption of ACT to the solid phase. To reduce the nonspecific interference, we produced an antibody specific for complexed ACT and developed immunofluorometric assays (IFMAs) for simultaneous measurement of fPSA + PSA-ACT (fPSA/PSA-ACT) and PSA-ACT + total PSA (tPSA, PSA-ACT/tPSA). Methods: Monoclonal antibodies (MAbs) were produced by immunization with PSA-ACT. The dual-label time-resolved IFMAs for fPSA/PSA-ACT and PSA-ACT/tPSA used a capture MAb to tPSA, an Eu3+-labeled MAb to fPSA or complexed ACT, and an Sm3+-labeled MAb to complexed ACT or to tPSA as tracer antibodies. The clinical utility was evaluated using serum samples from individuals with or without PCa with PSA concentrations of 2.0–20.0 μg/L. Results: One MAb (1D10) showed low cross-reactivity with free ACT and cathepsin G-ACT. A sandwich assay for PSA-ACT with 1D10 as tracer had a detection limit of 0.05 μg/L, and with this assay, PSA-ACT was undetectable in female sera. The detection limit for fPSA was 0.004 μg/L. Determinations of the ratio of fPSA to PSA-ACT and the proportions of fPSA/tPSA and PSA-ACT/tPSA provided the same clinical specificity for PCa and provided significantly better clinical specificity than did tPSA. Conclusions: Background problems observed in earlier PSA-ACT assays are eliminated by the use of a MAb specific for complexed ACT as a tracer. The same clinical validity can be obtained by determination of fPSA or PSA-ACT together or in combination with tPSA.

The value of (−7, −5)pro-prostate-specific antigen and human kallikrein-2 as serum markers for grading prostate cancer

2004 ◽  
Vol 93 (6) ◽  
pp. 720-724 ◽  
Author(s):  
C.H. Bangma ◽  
M.F. Wildhagen ◽  
G. Yurdakul ◽  
F.H. Schröder ◽  
B.G. Blijenberg
Keyword(s):  
Prostate Cancer ◽  
Prostate Specific Antigen ◽  
Specific Antigen ◽  
Serum Markers ◽  
Human Kallikrein 2 ◽  
Kallikrein 2

Discordant prostate specific antigen test results despite WHO assay standardization

2018 ◽  
Vol 33 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Martin Boegemann ◽  
Christian Arsov ◽  
Boris Hadaschik ◽  
Kathleen Herkommer ◽  
Florian Imkamp ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Early Detection ◽  
Specific Antigen ◽  
Test Results ◽  
Serum Samples ◽  
Prostate Specific Antigen Test ◽  
Free Psa ◽  
Prostate Biopsies ◽  
Cancer Early Detection ◽  
Total Psa

Introduction: Total PSA (tPSA) and free PSA (fPSA) are the most commonly used biomarkers for early detection of prostate cancer. Despite standardization efforts, many available PSA assays may still produce discordant results. In the present study, we compared four PSA assays calibrated to the WHO standards 96/670 and 96/668 for tPSA and fPSA, respectively. Methods: Within the scope of the Prostate Cancer Early Detection Study Based on a ‘‘Baseline’’ PSA Value in Young Men (PROBASE), we tested tPSA and fPSA in serum samples from 50 patients in the four different PROBASE sites using four WHO-calibrated assays from Roche (Elecsys, Cobas), Beckman-Coulter (Access-II) and Siemens (ADVIA Centaur). The comparison was performed using the Passing–Bablok regression method. Results: Compared to Access, the median tPSA levels for Centaur, Elecsys, and Cobas were +3%, +11%–20%, and +17%–23%, respectively, while for median fPSA levels the differences for Centaur, Elecsys, and Cobas were +49%, +29%–31%, and +22%, respectively. Discussion: Despite all investigated assays being WHO-calibrated, the Elecsys and Cobas tPSA assays produced considerably higher results than the Access and Centaur assays. Differences in fPSA-recovery between all investigated assays were even more pronounced. When applying the tPSA cutoff of 3.1 μg/L recommended for WHO-calibrated assays, the use of higher calibrated assays may lead to unnecessary prostate biopsies. Conversely, if the historical threshold of 4 μg/L is applied when using WHO-calibrated assays, it could lead to falsely omitted prostate biopsies.

scholarly journals Development of a Dual Monoclonal Antibody Immunoassay for Total Human Kallikrein 2

2001 ◽  
Vol 47 (7) ◽  
pp. 1218-1224 ◽  
Author(s):  
Judith A Finlay ◽  
John R Day ◽  
Cindy L Evans ◽  
Robert Carlson ◽  
Kristine Kuus-Reichel ◽  
...  
Keyword(s):  
Specific Antigen ◽  
High Specificity ◽  
Cross Reactivity ◽  
Minimum Detectable Concentration ◽  
Serum Samples ◽  
Bodily Fluids ◽  
Before And After ◽  
Detectable Concentration ◽  
Human Kallikrein 2 ◽  
Kallikrein 2

Abstract Background: Human kallikrein 2 (hK2) shares 80% sequence identity with prostate-specific antigen (PSA). Because both hK2 and hK2-α1-antichymotrypsin (hK2-ACT) complexes have been identified in patient sera, we devised an immunoassay for total hK2 [(thK2); hK2 and hK2-ACT] and evaluated it in healthy subjects and patients with prostate disease. Methods: We developed monoclonal antibodies (mAbs) with high specificity for hK2 and hK2-ACT and minimal cross-reactivity to PSA. Using these mAbs, a sandwich assay was developed and its specificity for forms of hK2 was assessed. Serum samples (n = 1035) from healthy volunteers, patients with increased PSA, and men who had undergone radical prostatectomy were assayed for thK2. We also measured thK2 in samples before and after storage under common laboratory conditions. Results: The minimum detectable concentration in the thK2 assay was 0.008 μg/L, and PSA cross-reactivity was <0.001%. The assay detected prohK2 and three different hK2–serum protease complexes. The median serum concentration of thK2 in control samples (0.013 μg/L) was significantly lower than the median in samples from patients with increased PSA concentrations (0.085 μg/L). Immunoreactive hK2 changed little in samples stored for up to 1 month at −70 °C. Conclusions: The thK2 assay recognizes all forms of hK2 that have been found in bodily fluids to date.

scholarly journals Glycomic Approach for Potential Biomarkers on Prostate Cancer: Profiling of N-Linked Glycans in Human Sera and pRNS Cell Lines

2008 ◽  
Vol 25 (4-5) ◽  
pp. 243-258 ◽  
Author(s):  
Maria Lorna A. de Leoz ◽  
Hyun Joo An ◽  
Scott Kronewitter ◽  
Jaehan Kim ◽  
Sean Beecroft ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Lines ◽  
Solid Phase ◽  
Specific Antigen ◽  
Ion Cyclotron Resonance ◽  
Serum Samples ◽  
Pngase F ◽  
Human Sera ◽  
Detect Prostate Cancer ◽  
Small Set

Prostate cancer is a leading cause of cancer death among men. Currently available screening test measures prostate-specific antigen (PSA) to detect prostate cancer. However, this test produces false positive values that often lead to negative biopsies. Therefore, a more reliable diagnostic tool is needed. Glycans in serum are of particular interest as around half of all proteins are glycosylated. In this study, N-linked glycans were enzymatically released by PNGase F from prostate epithelial cell lines (pRNS) expressing wild type or mutant androgen receptors and a small set of human serum samples. Released glycans were purified and partitioned into neutral and acidic components by solid phase extraction (SPE) using graphitized carbon cartridges. The SPE fractions were analyzed by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI FT-ICR MS). Significant changes in some high-mannose and fucosylated biantennary complex N-linked glycans were observed in the serum of prostate cancer patients.

Single Nucleotide Polymorphism of the Human Kallikrein-2 Gene Highly Correlates With Serum Human Kallikrein-2 Levels and in Combination Enhances Prostate Cancer Detection

2003 ◽  
Vol 21 (12) ◽  
pp. 2312-2319 ◽  
Author(s):  
Robert K. Nam ◽  
William W. Zhang ◽  
John Trachtenberg ◽  
Eleftherios Diamandis ◽  
Ants Toi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Odds Ratio ◽  
Adjusted Odds Ratio ◽  
Specific Antigen ◽  
Prostate Cancer Risk ◽  
Wild Type ◽  
Patients With Cancer ◽  
Prostate Biopsies ◽  
Human Kallikrein 2 ◽  
Kallikrein 2

Purpose: We examined the relationship between a mutant (T) for wild-type (C) allele substitution of the human kallikrein-2 gene (KLK2), circulating human kallikrein-2 (hK2) levels and prostate cancer risk.Patients and Methods: We studied 1,287 consecutive men who underwent prostate biopsies because of an abnormal prostate-specific antigen level. Serum and DNA were obtained before biopsy. Cases were patients with cancer, and controls were patients with no cancer. The mutant and wild-type alleles of the KLK2 gene were designated as the T and C alleles, respectively.Results: Of the 1,287 men, 616 had cancer, and 671 had no cancer. The overall distribution of the CC, CT, and TT KLK2 genotypes was 55.1%, 38.2%, and 6.8%, respectively. The median hK2 levels for men with the CC, CT, and TT genotypes were 0.24, 0.18, and 0.062 ng/mL and correlated with the genotypes, respectively (P = .0001). The adjusted odds ratios for prostate cancer for patients with the TT and CT genotypes compared with patients with the CC genotype, were 2.13 (95% confidence interval [CI], 1.3 to 3.5; P = .004) and 1.51 (95% CI, 1.2 to 2.0; P = .002), respectively. The adjusted odds ratio for prostate cancer for patients in the fourth quartile of hK2 compared with the first quartile was 4.33 (95% CI, 2.9 to 6.4; P = .0001). When combined, the adjusted odds ratio for having prostate cancer was 13.92 (95% CI, 6.6 to 29.2; P = .0001) for patients with high hK2 levels and at least one T allele.Conclusion: The C/T polymorphism of the KLK2 gene and circulating levels of hK2 are correlated and, in combination, are highly predictive for prostate cancer.

scholarly journals Early prediction of prostate cancer biochemical recurrence and identification of disease persistence using PSA isoforms and human kallikrein-2

Tumor Biology ◽  
2021 ◽  
Vol 43 (1) ◽  
pp. 197-207
Author(s):  
Joana Do Carmo Silva ◽  
Stepan Vesely ◽  
Hana Luksanova ◽  
Richard Prusa ◽  
Marko Babjuk
Keyword(s):  
Prostate Cancer ◽  
Biochemical Recurrence ◽  
Specific Antigen ◽  
Early Postoperative Period ◽  
P Value ◽  
Single Marker ◽  
Human Kallikrein 2 ◽  
Kallikrein 2 ◽  
Disease Persistence

BACKGROUND: The role of isoforms of prostate specific antigen (PSA) and other kallikrein-related markers in early detection of biochemical recurrence (BCR) after radical prostatectomy (RP) is not well known and serum PSA is currently used in preoperative risk nomograms. OBJECTIVE: The aim of this research was to study pre- and early postoperative levels of important PSA isoforms and human kallikrein-2 to determine their ability to predict BCR and identify disease persistence (DP). METHODS: This study included 128 consecutive patients who underwent RP for clinically localized prostate cancer. PSA, fPSA, %fPSA, [–2]proPSA, PHI and hK2 were measured preoperatively, at 1 and 3 months after RP. We determined the ability of these markers to predict BCR and identify DP. RESULTS: The DP and BCR rate were 11.7%and 20.3%respectively and the median follow up was 64 months (range 3–76 months). Preoperatively, the independent predictors of BCR were PSA (p-value 0.029), [–2]proPSA (p-value 0.002) and PHI (p-value 0.0003). Post-RP, PSA was the single marker correlating with BCR, both at one (p-value 0.0047) and 3 months (p-value 0.0004). PSA, fPSA, [–2]proPSA and PHI significantly correlated to DP at 1 and 3 months post-RP (p-value <  0.05), although PSA had the most significant existing correlation (p-value <  0.0001). CONCLUSIONS: [–2]proPSA and PHI are preoperative predictors of BCR and DP that outperform the currently used serum PSA. At the early postoperative period there is no additional benefit of the other markers tested.

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