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Do Carmo Silva J, Vesely S, Luksanova H, Prusa R, Babjuk M. Early prediction of prostate cancer biochemical recurrence and identification of disease persistence using PSA isoforms and human kallikrein-2. Tumour Biol 2021; 43:197-207. [PMID: 34486998 DOI: 10.3233/tub-211509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
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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Affiliation(s)
- Joana Do Carmo Silva
- Department of Urology, Second Faculty of Medicine of Charles University, University Hospital Motol, Prague, Czech Republic
| | - Stepan Vesely
- Department of Urology, Second Faculty of Medicine of Charles University, University Hospital Motol, Prague, Czech Republic
| | - Hana Luksanova
- Department of Medical Chemistry and Clinical Biochemistry, Second Faculty of Medicine of Charles University, University Hospital Motol, Prague, Czech Republic
| | - Richard Prusa
- Department of Medical Chemistry and Clinical Biochemistry, Second Faculty of Medicine of Charles University, University Hospital Motol, Prague, Czech Republic
| | - Marko Babjuk
- Department of Urology, Second Faculty of Medicine of Charles University, University Hospital Motol, Prague, Czech Republic.,Department of Urology, Medical University of Vienna, Austria
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Jakobsen NA, Hamdy FC, Bryant RJ. Novel biomarkers for the detection of prostate cancer. JOURNAL OF CLINICAL UROLOGY 2016; 9:3-10. [PMID: 28344810 PMCID: PMC5356177 DOI: 10.1177/2051415816656121] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/04/2016] [Indexed: 01/19/2023]
Abstract
Prostate-specific antigen (PSA) is widely used as a biomarker in the detection of prostate cancer and for decision making regarding treatment options, response to therapy, and clinical follow-up. Despite its widespread use, it is well recognised that PSA has suboptimal performance as a screening tool due to poor specificity, resulting in high negative biopsy rates and potential ‘over-diagnosis’ and ‘over-treatment’ of clinically insignificant cancers. In particular, PSA does not reliably distinguish either cancer from benign prostatic conditions, or ‘clinically significant’ from ‘indolent cancers’, and it is inaccurate in predicting disease burden and response to treatment. There is an urgent demand for novel biomarkers to address these clinical needs. This article provides an update on the novel candidate biomarkers in development, which have shown potential for improving the detection of clinically significant cases of this malignancy.
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Bachour DM, Chahin E, Al-Fahoum S. Human Kallikrein-2, Prostate Specific Antigen and Free- Prostate Specific Antigen in Combination to Discriminate Prostate Cancer from Benign Diseases in Syrian Patients. Asian Pac J Cancer Prev 2016; 16:7085-8. [PMID: 26514494 DOI: 10.7314/apjcp.2015.16.16.7085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The high incidence of prostate cancer as the most common malignancy in males in many countries raises the question of developing reliable detection tests. The prostate specific antigen (PSA) test is the most widely used for screening for prostate cancer; however, its low specificity elevates the number of unnecessarily biopsies. Serum human kallikrein-2 (hK2) is considered as a promising marker, and especially its ratio to fPSA, for predicting the presence of malignancy to select the best choice referring to biopsy or surveillance. In this study, we investigated the role of hK2 and its combinations with other markers to discriminate prostate cancer from benign diseases in Syrian patients. MATERIALS AND METHODS In this prospective oriented cross-sectional cohort study, serum samples were collected from patients referred to many Hospitals in Damascus, Syria, between May 2011 and March 2012, and diagnosed with biopsy proven benign prostate hyperplasia (BPH) or prostate cancer (PCa). Serum was analyzed for hK2, PSA and fPSA, and the ratios of fPSA/PSA and hK2/fPSA were calculated. RESULTS We found that mean hK2/fPSA ratios were significantly higher (P=0.01) in prostate cancer patients than in the BPH or control groups. Also the ratio hk2/fPSA gave the largest area under the curve (AUC:0.96) which was significantly larger than for fPSA/PSA (AUC:0.41) indicative of higher specificity. CONCLUSIONS Our results demonstrate that the ratio of hK2/fPSA might be superior to the use of fPSA/PSA alone. The hK2 could be shown to enhance the early detection of prostate cancer; especially the ratio hK2/fPSA improves specificity and hence may reduce the number of negative biopsies.
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Affiliation(s)
- Dala-Maria Bachour
- Master Student, Faculty of Pharmacy, Damascus University, Syria E-mail :
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Schmid M, Hansen J, Rink M, Fisch M, Chun F. The development of nomograms for stratification of men at risk of prostate cancer prior to prostate biopsy. Biomark Med 2014; 7:843-50. [PMID: 24266817 DOI: 10.2217/bmm.13.114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A main limitation of early prostate cancer (PCa) detection due to elevated PSA levels is caused by the low specificity of PSA, which is associated with a high proportion of men detected with nonmalignant findings at first or subsequent prostate biopsy (PBX). Multivariate prediction models, such as nomograms, have been developed, providing a more accurate method to prospectively determine the risk of a positive PBX. Combining established clinical risk factors with novel diagnostic markers of PCa appears promising to further improve predictive accuracy estimates. Ideally, these nomograms should be capable of identifying PCa at PBX without missing men with high-grade PCa, and preventing a significant proportion of men without, or with insignificant, PCa from undergoing PBX. The intention is to reduce disease morbidity and mortality by detecting significant PCa at an early stage, and at the same time to avoid overdiagnosis as well as overintervention.
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Affiliation(s)
- Marianne Schmid
- Department of Urology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
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Schmid M, Trinh QD, Graefen M, Fisch M, Chun FK, Hansen J. The role of biomarkers in the assessment of prostate cancer risk prior to prostate biopsy: which markers matter and how should they be used? World J Urol 2014; 32:871-80. [PMID: 24825472 DOI: 10.1007/s00345-014-1317-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 05/02/2014] [Indexed: 12/12/2022] Open
Abstract
Prostate cancer (PCa) screening has been substantially influenced by the clinical implementation of serum prostate-specific antigen (PSA). In this context, improvement of early PCa detection and stage migration as well as reduced PCa mortality were achieved, and up-to-date PSA represents the gold standard biomarker of PCa diagnosis together with clinical findings. Nonetheless, PSA shows weakness in discriminating between malign and benign prostatic disease or indolent and aggressive cancers. As a result, the expansion of PSA screening is extensively debated with regard to overdetection and ultimately overtreatment, keeping in mind that PCa is still the third leading cause of cancer-specific mortality in the Western male population. Consequently, today's task is to increase the accuracy of PCa detection and furthermore to allow stratification for indolent PCa that might permit active surveillance and to filter out aggressive cancers necessitating treatment. Thus, novel biomarkers, especially in combination with approved clinical risk factors (e.g., age or family history of PCa), within multivariable prediction models carry the potential to improve many aspects of PCa diagnosis and to enable risk classification in clinical practice. Multivariable models lead to superior accuracy for PCa prediction instead of the use of a single risk factor. The aim of this article was to present an overview of known risk factors for PCa together with new promising blood- and urine-based biomarkers and their application within risk models that may allow risk stratification for PCa prior to prostate biopsy. Risk models may optimize PCa detection and classification with regard to improved PCa risk assessment and avoidance of unnecessary prostate biopsies.
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Affiliation(s)
- Marianne Schmid
- Department of Urology, University Hospital Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
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Abstract
Prostate cancer (PCa), a highly heterogeneous disease, is the one of the leading cause of morbidity and mortality in the developed countries. Historically used biomarkers such as prostatic acid phosphatase (PAP), serum prostate-specific antigen (PSA), and its precursor have not stood the challenge of sensitivity and specificity. At present, there is need to re-evaluate the approach to diagnose and monitor PCa. To this end, molecular markers that can accurately identify men with PCa at an early stage, and those who would benefit from early therapeutic intervention, are the need of the hour. There has been unprecedented progress in the development of new PCa biomarkers through advancements in proteomics, tissue DNA and protein/RNA microarray, identification of microRNA, isolation of circulating tumor cells, and tumor immunohistochemistry. This review will examine the current status of prostate cancer biomarkers with emphasis on emerging biomarkers by evaluating their diagnostic and prognostic potentials.
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Affiliation(s)
- Tapan Bhavsar
- Department of Pathology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Hansen J, Rink M, Graefen M, Shariat S, Chun FKH. Assays for prostate cancer : changing the screening paradigm? Mol Diagn Ther 2013; 17:1-8. [PMID: 23355098 DOI: 10.1007/s40291-013-0014-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Prostate cancer (PCa) screening and detection have changed dramatically since the introduction of serum prostate-specific antigen (PSA) testing. Despite the resulting improvement in early PCa detection and stage migration, in clinical practice the use of PSA testing may cause overdetection and ultimately overtreatment. As a consequence, novel biomarkers are needed to increase the specificity of PCa detection. The aim of this article is to present an overview of novel blood- and urine-based biomarkers that may optimize PCa detection, with improved identification of patients with significant PCa and avoidance of unnecessary prostate biopsies. A systematic and comprehensive PubMed search was performed using the MeSH search terms 'prostate cancer', 'biomarker', 'marker', and 'detection'. Results were restricted to the English language. Several blood- and urine-based biomarkers have the potential to improve prediction of the presence and/or significance of PCa. Ideally, biomarkers should be used in combination within multivariate models, leading to superior accuracy for prediction of any PCa or clinically significant PCa, compared with the use of a single marker.
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Affiliation(s)
- Jens Hansen
- Department of Urology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
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Zhu X, Albertsen PC, Andriole GL, Roobol MJ, Schröder FH, Vickers AJ. Risk-based prostate cancer screening. Eur Urol 2011; 61:652-61. [PMID: 22134009 DOI: 10.1016/j.eururo.2011.11.029] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 11/15/2011] [Indexed: 11/30/2022]
Abstract
CONTEXT Widespread mass screening of prostate cancer (PCa) is not recommended because the balance between benefits and harms is still not well established. The achieved mortality reduction comes with considerable harm such as unnecessary biopsies, overdiagnoses, and overtreatment. Therefore, patient stratification with regard to PCa risk and aggressiveness is necessary to identify those men who are at risk and may actually benefit from early detection. OBJECTIVE This review critically examines the current evidence regarding risk-based PCa screening. EVIDENCE ACQUISITION A search of the literature was performed using the Medline database. Further studies were selected based on manual searches of reference lists and review articles. EVIDENCE SYNTHESIS Prostate-specific antigen (PSA) has been shown to be the single most significant predictive factor for identifying men at increased risk of developing PCa. Especially in men with no additional risk factors, PSA alone provides an appropriate marker up to 30 yr into the future. After assessment of an early PSA test, the screening frequency may be determined based on individualized risk. A limited list of additional factors such as age, comorbidity, prostate volume, family history, ethnicity, and previous biopsy status have been identified to modify risk and are important for consideration in routine practice. In men with a known PSA, risk calculators may hold the promise of identifying those who are at increased risk of having PCa and are therefore candidates for biopsy. CONCLUSIONS PSA testing may serve as the foundation for a more risk-based assessment. However, the decision to undergo early PSA testing should be a shared one between the patient and his physician based on information balancing its advantages and disadvantages.
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Affiliation(s)
- Xiaoye Zhu
- Department of Urology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
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Shariat SF, Semjonow A, Lilja H, Savage C, Vickers AJ, Bjartell A. Tumor markers in prostate cancer I: blood-based markers. Acta Oncol 2011; 50 Suppl 1:61-75. [PMID: 21604943 PMCID: PMC3571678 DOI: 10.3109/0284186x.2010.542174] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
UNLABELLED The introduction of total prostate specific antigen (total PSA) testing in blood has revolutionized the detection and management of men with prostate cancer (PCa). The objective of this review was to discuss the challenges of PCa biomarker research, definition of the type of PCa biomarkers, the statistical considerations for biomarker discovery and validation, and to review the literature regarding total PSA velocity and novel blood-based biomarkers. METHODS An English-language literature review of the Medline database (1990 to August 2010) of published data on blood-based biomarkers and PCa was undertaken. RESULTS The inherent biological variability of total PSA levels affects the interpretation of any single result. Men who will eventually develop PCa have increased total PSA levels years or decades before the cancer is diagnosed. Total PSA velocity improves predictiveness of total PSA only marginally, limiting its value for PCa screening and prognostication. The combination of PSA molecular forms and other biomarkers improve PCa detection substantially. Several novel blood-based biomarkers such as human glandular kallikrein 2 (hK2), urokinase plasminogen activator (uPA) and its receptor (uPAR), transforming growth factor-beta 1 (TGF-β1); interleukin-6 (IL-6) and its receptor (IL-6R) may help PCa diagnosis, staging, prognostication, and monitoring. Panels of biomarkers that capture the biologic potential of PCa are in the process of being validated for PCa prognostication. CONCLUSIONS PSA is a strong prognostic marker for long-term risk of clinically relevant cancer. However, there is a need for novel biomarkers that aid clinical decision making about biopsy and initial treatment. There is no doubt that progress will continue based on the integrated collaboration of researchers, clinicians and biomedical firms.
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Affiliation(s)
- Shahrokh F. Shariat
- Department of Urology and Medical Oncology, Weill Cornell Medical Center, New York, NY, USA
| | - Axel Semjonow
- Department of Urology, Prostate Center, University Hospital Muenster, Muenster, Germany
| | - Hans Lilja
- Department of Surgery (Urology Service), Clinical Laboratories, and Medicine (Genito-Urinary Oncology Service), Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Caroline Savage
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Andrew J. Vickers
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Anders Bjartell
- Department of Urology Malmö-Lund, Skåne University Hospital, Lund University, Sweden
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Djavan B, Kazzazi A, Dulabon L, Margreiter M, Farr A, Handl MJ, Lepor H. Diagnostic Strategies for Prostate Cancer. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.eursup.2011.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Bangma CH, van Schaik RH, Blijenberg BG, Roobol MJ, Lilja H, Stenman UH. On the use of prostate-specific antigen for screening of prostate cancer in European Randomised Study for Screening of Prostate Cancer. Eur J Cancer 2010; 46:3109-19. [DOI: 10.1016/j.ejca.2010.09.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 09/16/2010] [Accepted: 09/17/2010] [Indexed: 10/18/2022]
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Christensson A, Bruun L, Björk T, Cronin AM, Vickers AJ, Savage CJ, Lilja H. Intra-individual short-term variability of prostate-specific antigen and other kallikrein markers in a serial collection of blood from men under evaluation for prostate cancer. BJU Int 2010; 107:1769-74. [PMID: 20955263 DOI: 10.1111/j.1464-410x.2010.09761.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
STUDY TYPE Diagnostic (exploratory cohort). LEVEL OF EVIDENCE 2b. OBJECTIVE To assess variation of total prostate-specific antigen (tPSA), free PSA (fPSA), percent fPSA, human glandular kallikrein 2 (hK2) and intact PSA measured three times within 2 weeks. Knowledge of the variation in an individual's PSA level is important for clinical decision-making. PATIENTS AND METHODS Study participants were 149 patients referred for prostate biopsy, of which 97 had benign disease and 52 had prostate cancer. Three blood samples were drawn with a median of 4 h between first and second samples and 12 days between first and third samples. Variability was described by absolute differences, ratios and intra-individual coefficients of variation. Total PSA, fPSA, hK2 and intact PSA were measured in anticoagulated blood plasma. RESULTS At baseline, the median tPSA was 6.8 (interquartile range, 4.5-9.6) ng/mL. The intra-individual variation was low for all biomarkers, and lowest for tPSA. For 80% of participants, the ratio between first and second time points for tPSA was in the range 0.91-1.09 and the ratio for percent fPSA was in the range 0.89-1.15. Total coefficients of variation between time 1 and 2 for tPSA, fPSA, percent fPSA, hK2 and intact PSA were 4.0%, 6.6%, 6.0%, 9.2% and 9.5%, respectively. The measurements taken several days apart varied more than those taken on the same day, although the variation between both time points was not large. CONCLUSIONS The intra-individual variation for all the kallikrein-like markers studied was relatively small, especially for samples drawn the same day. Few cases are reclassified between the time points. This indicates the high short-term biological and technical reproducibility of the tests in clinical use.
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Affiliation(s)
- Anders Christensson
- Division of Nephrology, Department of Clinical Sciences, Lund University, University Hospital, Malmö, Sweden.
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Mazzola CRE, Ghoneim T, Shariat SF. [Emerging biomarkers for the diagnosis, staging and prognosis of prostate cancer]. Prog Urol 2010; 21:1-10. [PMID: 21193139 DOI: 10.1016/j.purol.2010.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 07/01/2010] [Indexed: 11/30/2022]
Abstract
The introduction and widespread adoption of prostate-specific antigen (PSA) has revolutionized the way prostate cancer is diagnosed and treated. However, the use of PSA has also led to overdiagnosis and overtreatment of prostate cancer resulting in controversy about its use for screening. PSA also has limited predictive accuracy for predicting outcomes after treatment and for making clinical decisions about adjuvant and salvage therapies. Hence, there is an urgent need for novel biomarkers to supplement PSA for detection and management of prostate cancer. A plethora of promising blood- and urine-based biomarkers have shown promise in early studies and are at various stages of development (Human kallikrein 2, Early Prostate Cancer Antigen, Transforming Growth Factor-Beta 1 and Interleukin-6, Endoglin, PCA3, AMACR and ETS Gene Fusions). In this article, we review those biomarkers and then discuss the challenges a biomarker has to undergo before it is approved in a clinical use.
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Affiliation(s)
- C R E Mazzola
- Department of Clinical Laboratories, Memorial Sloan-Kettering Cancer Center, 1275, York Avenue, New York City, NY 10065, États-Unis.
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Korbakis D, Gregorakis AK, Scorilas A. Quantitative Analysis of Human Kallikrein 5 (KLK5) Expression in Prostate Needle Biopsies: An Independent Cancer Biomarker. Clin Chem 2009; 55:904-13. [DOI: 10.1373/clinchem.2008.103788] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
Background: Kallikrein 5 (KLK5), a recently cloned member of the kallikrein family, codes for the secreted protein KLK5. Active KLK5 protein has a trypsin activity, and the expression of KLK5 gene seems to be regulated by steroid hormones. We performed an expression analysis and clinical evaluation of the KLK5 gene, at the mRNA level, in prostate needle biopsies.
Methods: We examined KLK5 mRNA concentrations in 103 prostate tissue specimens. After testing of RNA quality, cDNA was prepared by reverse transcription. A highly sensitive quantitative real-time PCR (qRT-PCR) method for KLK5 mRNA quantification was developed using the SYBR Green chemistry. GAPDH was used as a housekeeping gene.
Results: Specimens from patients with benign prostatic hyperplasia (BPH) showed higher levels of KLK5 mRNA expression than those from patients with prostate cancer (PCa) (P = 0.024). ROC analysis demonstrated that KLK5 expression had significant discriminatory value between BPH and PCa (AUC 0.64; P = 0.016). KLK5 mRNA expression showed a statistically significant negative correlation with the total PSA serum concentration in the PCa patients (P = 0.003). Early-stage tumors showed higher KLK5 expression than late-stage ones (P = 0.014), whereas KLK5 expression was negatively correlated to Gleason score (P = 0.005).
Conclusions: KLK5 mRNA, analyzed by quantitative PCR in prostate needle biopsies, could be an independent biomarker for the differential diagnosis and prognosis in prostate cancer.
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Affiliation(s)
- Dimitrios Korbakis
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Athens, Athens, Greece
| | - Alkiviades K Gregorakis
- 2nd Department of Urology, Faculty of Medicine, University of Athens, Attikon Hospital, Athens, Greece
| | - Andreas Scorilas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Athens, Athens, Greece
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Jansen FH, Roobol M, Jenster G, Schröder FH, Bangma CH. Screening for prostate cancer in 2008 II: the importance of molecular subforms of prostate-specific antigen and tissue kallikreins. Eur Urol 2008; 55:563-74. [PMID: 19058905 DOI: 10.1016/j.eururo.2008.11.040] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 11/21/2008] [Indexed: 11/17/2022]
Abstract
CONTEXT Over the past decades, prostate-specific antigen (PSA), its isoforms, and other members of the tissue kallikrein family have been of continuous interest with regard to early detection and screening for prostate cancer (PCa). OBJECTIVE This review strives to give an overview of the possible clinical utilities of these markers, focused on early diagnostics and PCa screening. EVIDENCE ACQUISITION Using the Medline database, a literature search was performed on the role of molecular subforms of PSA and other members of the tissue kallikrein family in PCa detection. EVIDENCE SYNTHESIS With respect to PSA isoforms, only the combination of the various truncated forms (pPSA) shows additional value over total PSA (tPSA) and free PSA (fPSA) in PCa detection within the range of 2-10 ng/ml tPSA. At a high sensitivity for PCa, the specificity of the ratio of pPSA to fPSA (%pPSA) is, in general, better than that of the ratio of fPSA to tPSA (%fPSA), with a gain of 5-11%. The (-2)pPSA, (-4)pPSA, (-5)pPSA, (-7)pPSA, and benign PSA (BPSA) isoforms generally show no additional value over either pPSA or the existing parameters of tPSA and fPSA. Of the other members of the tissue kallikrein family, most studies on human kallikrein 2 (hK2) show an additional value of the ratio of hK2 to fPSA (%hK2) over %fPSA alone in PCa prediction. Other tissue kallikreins cannot be recommended for diagnosing PCa, due to the lack of additional value over tPSA or fPSA or to insufficient research. Regarding a prognostic role, the value of PSA subforms as well as of other members of the tissue kallikrein family is limited with regard to existing parameters. CONCLUSIONS pPSA and hK2 are able to improve PCa diagnosis in the range of 4-10 ng/ml tPSA over the existing variables tPSA and fPSA.
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Affiliation(s)
- Flip H Jansen
- Department of Urology, Erasmus MC, Rotterdam, The Netherlands.
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Alapont Alacreu JM, Navarro Rosales S, Budía Alba A, España Furió F, Morera Martínez F, Jiménez Cruz JF. [PSA and hK2 in the diagnosis of prostate cancer]. Actas Urol Esp 2008; 32:575-88. [PMID: 18655340 DOI: 10.1016/s0210-4806(08)73891-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Serum markers for prostate carcinoma are widely applied for the purpose of early detection of cancer and the differentiation between benign and malignant disease, for the pre-treatment staging of detected prostatic cancers, and for the monitoring of prostate cancer after curative or palliative therapies. Since its discovery in 1979, serum PSA has been the most powerful marker of prostate cancer, but, when used alone, PSA is not sufficiently sensitive or specific to consider it an ideal tool for the early detection or staging of prostate cancer. To optimize the use of PSA, the concepts of PSA velocity, PSA density, and age-related PSA values were developed. Moreover, the molecular forms of PSA, especially the percentage of free PSA, seem to be useful tools for the detection of prostate cancer in men with slightly elevated total PSA. Human kallikrein 2 (hK2), a serine protease closely related to PSA that also is expressed predominantly in the prostate, is a new complementary marker to PSA for early detection of prostate cancer. In this review, we examine PSA testing and its effectiveness in the diagnosis of prostate cancer. Further, we also evaluate recent literature regarding the use of hk2.
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Clements JA, Willemsen NM, Myers SA, Dong Y. The Tissue Kallikrein Family of Serine Proteases: Functional Roles in Human Disease and Potential as Clinical Biomarkers. Crit Rev Clin Lab Sci 2008; 41:265-312. [PMID: 15307634 DOI: 10.1080/10408360490471931] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Prostate specific antigen (PSA) or human kallikrein 3 (hK3) has long been an effective biomarker for prostate cancer. Now, other members of the tissue kallikrein (KLK) gene family are fast becoming of clinical interest due to their potential as prognostic biomarkers. particularly for hormone dependent cancers. The tissue kallikreins are serine proteases that are encoded by highly conserved multi-gene family clusters in rodents and humans. The rat and mouse loci contain 10 and 25 functional genes, respectively, while the human locus at 19q 13.4 contains 15 genes. The structural organization and size of these genes are similar across species; all genes have 5 coding exons that encode a prepro-enzyme. Although the physiological activators of these zymogens have not been described, in vitro biochemical studies show that some kallikreins can auto-activate and others can activate each other, suggesting that the kallikreins may participate in an enzymatic cascade similar to that of the coagulation cascade. These genes are expressed, to varying degrees, in a wide range of tissues suggesting a functional involvement in a diverse range of physiological and pathophysiological processes. These include roles in normal skin desquamation and psoriatic lesions, tooth development, neural plasticity, and Alzheimer's disease (AD). Of particular interest is the expression of many kallikreins in prostate, ovarian, and breast cancers where they are emerging as useful prognostic indicators of disease progression.
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Affiliation(s)
- Judith A Clements
- Hormone Dependent Cancer Program, Cluster for Molecular Biotechnology, School of Life Sciences & Science Research Centre, Queensland University of Technology, Brisbane, Australia.
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Vickers AJ, Cronin AM, Aus G, Pihl CG, Becker C, Pettersson K, Scardino PT, Hugosson J, Lilja H. A panel of kallikrein markers can reduce unnecessary biopsy for prostate cancer: data from the European Randomized Study of Prostate Cancer Screening in Göteborg, Sweden. BMC Med 2008; 6:19. [PMID: 18611265 PMCID: PMC2474851 DOI: 10.1186/1741-7015-6-19] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 07/08/2008] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Prostate-specific antigen (PSA) is widely used to detect prostate cancer. The low positive predictive value of elevated PSA results in large numbers of unnecessary prostate biopsies. We set out to determine whether a multivariable model including four kallikrein forms (total, free, and intact PSA, and human kallikrein 2 (hK2)) could predict prostate biopsy outcome in previously unscreened men with elevated total PSA. METHODS The study cohort comprised 740 men in Göteborg, Sweden, undergoing biopsy during the first round of the European Randomized study of Screening for Prostate Cancer. We calculated the area-under-the-curve (AUC) for predicting prostate cancer at biopsy. AUCs for a model including age and PSA (the 'laboratory' model) and age, PSA and digital rectal exam (the 'clinical' model) were compared with those for models that also included additional kallikreins. RESULTS Addition of free and intact PSA and hK2 improved AUC from 0.68 to 0.83 and from 0.72 to 0.84, for the laboratory and clinical models respectively. Using a 20% risk of prostate cancer as the threshold for biopsy would have reduced the number of biopsies by 424 (57%) and missed only 31 out of 152 low-grade and 3 out of 40 high-grade cancers. CONCLUSION Multiple kallikrein forms measured in blood can predict the result of biopsy in previously unscreened men with elevated PSA. A multivariable model can determine which men should be advised to undergo biopsy and which might be advised to continue screening, but defer biopsy until there was stronger evidence of malignancy.
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Affiliation(s)
- Andrew J Vickers
- Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics, East 63rd Street, New York, NY 10021, USA.
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Kaushal A, Myers SA, Dong Y, Lai J, Tan OL, Bui LT, Hunt ML, Digby MR, Samaratunga H, Gardiner RA, Clements JA, Hooper JD. A novel transcript from the KLKP1 gene is androgen regulated, down-regulated during prostate cancer progression and encodes the first non-serine protease identified from the human kallikrein gene locus. Prostate 2008; 68:381-99. [PMID: 18196551 DOI: 10.1002/pros.20685] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The kallikrein-related (KLK) serine protease, prostate specific antigen is the current marker for prostate cancer (PCa). Other members of the KLK family are also emerging as potential adjunct biomarkers for this disease. Our aim was to identify and characterize novel KLK-related genes with potential as PCa bio-markers. METHODS Low stringency DNA screening was coupled with amplification techniques to identify novel sequences. Transcripts were examined by Northern blot, RT-PCR, and in situ hybridization analysis and in silico bioinformatics approaches. Protein characterization was performed by Western blot and confocal microscopy analysis. Gene regulation studies were performed by quantitative PCR and promoter reporter assays. RESULTS We identified a novel kallikrein-related mRNA designated KRIP1 (kallikrein-related, expressed in prostate 1) which, together with the recently reported PsiKLK1 and KLK31P transcripts, is transcribed from KLKP1; a gene evolved from, and located within, the KLK locus. Significantly, in contrast to these other non-coding KLKP1 transcripts, the KRIP1 mRNA generates an approximately 18 kDa intracellular protein-the first non-serine protease identified from the KLK locus. KRIP1 mRNA is abundant only in normal prostate and is restricted to cells of epithelial origin in normal and diseased glands. Ligand binding of the androgen receptor increases transcription from the KLKP1 gene. Consistently, KRIP1 mRNA levels are lower in PCa samples compared to benign prostatic hyperplasia. CONCLUSIONS Transcription from KLKP1 is reduced as cells de-differentiate on the pathway to malignancy. KLKP1/KRIP1 has potential as a marker of both PCa progression and recent evolutionary events within the KLK locus.
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Affiliation(s)
- Aneel Kaushal
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia
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Abstract
The introduction of prostate-specific antigen (PSA) revolutionized prostate cancer (PCa) screening and ushered the PSA era. However, its use as a screening tool remains controversial and changes in the epidemiology of PCa have strongly limited its prognostic role. Therefore, we need novel approaches to improve our ability to detect PCa and foretell the course of the disease. To improve the specificity of total PSA, several approaches based on PSA derivatives have been investigated such as age-specific values, PSA density (PSAD), PSAD of the transition zone, PSA velocity and assessment of various isoforms of PSA. With recent advances in biotechnology such as high-throughput molecular analyses, many potential blood biomarkers have been identified and are currently under investigation. Given the plethora of candidate PCa biomarkers, we have chosen to discuss a select group of candidate blood-based biomarkers including human glandular kallikrein, early prostate cancer antigens, insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBP-2 and IGFBP-3), urokinase plasminogen activation system, transforming growth factor-beta1, interleukin-6, chromogranin A, prostate secretory protein, prostate-specific membrane antigen, PCa-specific autoantibodies and alpha-methylacyl-CoA racemase. While these and other markers have shown promise in early phase studies, no single biomarker is likely to have the appropriate degree of certainty to dictate treatment decisions. Consequently, the future of cancer prognosis may rely on small panels of markers that can accurately predict PCa presence, stage, metastasis, and serve as prognosticators, targets and/or surrogate end points of disease progression and response to therapy.
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Raaijmakers R, de Vries SH, Blijenberg BG, Wildhagen MF, Postma R, Bangma CH, Darte C, Schröder FH. hK2 and free PSA, a prognostic combination in predicting minimal prostate cancer in screen-detected men within the PSA range 4-10 ng/ml. Eur Urol 2007; 52:1358-64. [PMID: 17499425 DOI: 10.1016/j.eururo.2007.04.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Accepted: 04/11/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES The purpose of screening for prostate cancer is to decrease the disease-specific mortality. However not every screen-detected prostate cancer is a threat to the patient's life. The risk of overdetection and subsequent overtreatment in prostate cancer has been recognised. The purpose of this investigation was to evaluate the role of tumour markers total PSA, free PSA, and hK2, and their combinations in predicting minimal prostate cancer. METHODS Within the European Randomized Study of Screening for Prostate Cancer (ERSPC), section Rotterdam, The Netherlands, prebiopsy serum samples were analysed for 100 selected men who underwent a radical prostatectomy for their screen-detected prostate cancer. All had a PSA value between 4 and 10 ng/ml prior to diagnosis. Minimal prostate cancer is defined as organ confined, Gleason score </=6 (no Gleason grade 4 or 5), and tumour volume <0.5 ml. RESULTS Sera and tumour volumes from 91 men were available for analysis. Minimal prostate cancer was diagnosed in 16.5% of the selected cases. Mean tumour volume was 1.2 ml (range: 0.04-13.5); hK2, the algorithms hK2/fPSA, and hK2/%fPSA have significant correlations with tumour volume. Both algorithms also yielded the best test results in predicting minimal disease with an area under the receiver operator characteristics curve of 82%. CONCLUSIONS hK2 and percent free PSA have added prognostic value for the detection of minimal prostate cancer in screen-detected cases within PSA range 4-10 ng/ml. These biomarkers can possibly be used to select less invasive treatment options like active surveillance and to prevent overtreatment.
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Abstract
Molecular forms of serum PSA (prostate specific antigen) have been developped to improve total PSA sensitivity and specificity in prostate cancer diagnosis and staging. Total PSA is measured in bound (complexed PSA) and unbound (free PSA) molecular forms. Their levels in absolute values and in relation to total PSA (f/t PSA and c/t PSA) have been evaluated. The percentage of free PSA is more specific but less sensitive than tPSA and it is not recommended as a first line diagnostic test. It may be useful as a second-line test, prescribed by the urologist after a first series of negative biopsies. There is general agreement that at high sensitivity, cPSA provides higher specificity compared with tPSA in the gray zone (2-10 ng/ml). Nevertheless the widespread use of tPSA an the small benefit in terms of specificity explains why cPSA is not generally recommanded. Molecular derivates of free PSA have been identified: proPSA (precursor inactive form of PSA), intact PSA (an additionnal form of proPSA that is found intact and inactive), human Kallikrein 2 and BPSA (for benign PSA wich is associated to BPH) have been evaluated. Preliminary studies did not have demonstrate their ability to discriminate between cancer and BPH, and did not define cutoff values.
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Steuber T, Helo P, Lilja H. Circulating biomarkers for prostate cancer. World J Urol 2007; 25:111-9. [PMID: 17345087 DOI: 10.1007/s00345-007-0160-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Accepted: 02/02/2007] [Indexed: 10/23/2022] Open
Abstract
Due to its significant applicability for early detection, risk prediction and follow-up evaluation, prostate specific antigen (PSA) has revolutionized our ability to treat prostate cancer patients. With the prevalent use of PSA for early detection during the last two decades, disease characteristics have been altered towards early detected, localized tumors with a high chance of cure following local therapy. This advantage faces the risk of overdetection and overtreatment. In addition, PSA lacks both, sensitivity and specificity to accurately detect patients at risk of prostate cancer. Therefore, novel biomarkers are urgently needed to improve identification of men at risk of having the disease and to predict the natural behaviour of the tumor. Recent advances in the evaluation of high-throughput technologies have led to the discovery of novel candidate markers for prostate cancer. This article will briefly discuss current PSA-based strategies and review several novel biomarkers for prostate cancer, detectable in blood.
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Affiliation(s)
- Thomas Steuber
- Department of Urology, University Clinic Hamburg Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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Abstract
Screening for prostate cancer is currently based on the assessment of blood prostate specific antigen (PSA). Although PSA was shown to be an adequate tool in prostate cancer screening, beginning from 4.0 ng/mL, its specificity is less significant. In men with a PSA between 4.0 and 10 ng/mL its predictive value is low. Therefore, there is a need for new instruments likely to improve the specificity of blood PSA levels between 4.0 and 10 ng/mL and the screening for prostate cancer in subjects with low PSA. Recent data are reviewed.
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Affiliation(s)
- C Seitz
- Dept. of Urology, Medical University of Vienna, 18-20, Xähringer-Gürte, 1090 Vienna, Austria
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Abstract
Although prostate-specific antigen (PSA) has evolved as a very useful tool for detection of prostate cancer, there remains an urgent need for more accurate biomarkers to diagnose prostate cancer and predict cancer-related outcomes. Recent advances in the study of proteomics and high throughput techniques have led to the discovery of many potential biomarkers for prostate cancer. This article briefly reviews the current status of PSA testing and discusses several candidate protein biomarkers for prostate cancer, as well as highlighting some recent proteomic discoveries with the potential to supplement or even replace PSA for the diagnosis and prognosis of prostate cancer.
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Affiliation(s)
- Timothy J Bradford
- Department of Urology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Väisänen V, Pettersson K, Alanen K, Viitanen T, Nurmi M. Free and total human glandular kallikrein 2 in patients with prostate cancer. Urology 2006; 68:219-25. [PMID: 16844459 DOI: 10.1016/j.urology.2006.01.075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 12/27/2005] [Accepted: 01/30/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVES The use of prostate-specific antigen (PSA, hK3) results in the overdiagnosis and overtreatment of prostate cancer. Markers are needed that could identify aggressive, fast-growing tumors and help decide which patients would benefit most from aggressive treatment. Human glandular kallikrein 2 (hK2) could be such a marker. The aim of this study was to test how PSA and hK2 could predict the pathologic stage and grade in a set of patients with clinically organ-confined disease. METHODS Heparin plasma was collected from 188 patients who had undergone radical prostatectomy at the Turku University Central Hospital. Total and free PSA, as well as total and free hK2, were measured and the results compared with the pathologic TNM stage, tumor World Health Organization grade, and Gleason score. RESULTS Free and total hK2 performed similarly to PSA in their ability to separate groups of patients with different stages or grades. Concentrations of both kallikreins were significantly different in patients with World Health Organization grade 1 cancer compared with grade 2. Neither marker could separate patients with different Gleason scores. Although PSA concentrations increased most between patients with Stage pT2b and those with pT3a, the increase in hK2 was most pronounced between those with Stage pT3a and those with pT3b. CONCLUSIONS Although hK2 could not predict the cancer stage or grade better than PSA, changes in the hK2 and PSA concentrations occurred at different points in cancer progression. hK2 may have a role in the prognosis of prostate cancer, but additional studies with longer follow-up are required to determine whether hK2 can help when selecting treatment options.
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Affiliation(s)
- Ville Väisänen
- Department of Biotechnology, University of Turku, Turku, Finland.
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Martin BJ, Cheli CD, Sterling K, Ward M, Pollard S, Lifsey D, Mercante D, Martin L, Rayford W. Prostate Specific Antigen Isoforms and Human Glandular Kallikrein 2—Which Offers the Best Screening Performance in a Predominantly Black Population? J Urol 2006; 175:104-7. [PMID: 16406882 DOI: 10.1016/s0022-5347(05)00069-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Indexed: 11/30/2022]
Abstract
PURPOSE Free prostate specific antigen, complexed PSA and human glandular kallikrein 2 have independently been tested against the gold standard of total PSA for prostate cancer screening in largely white populations. With the incidence of prostate cancer much higher in black men, we sought to evaluate these markers simultaneously in a predominantly black population. MATERIALS AND METHODS A total of 138 men, of whom 108 were black, underwent ultrasound guided biopsy of the prostate for tPSA levels greater than 2.5 ng/ml or an abnormal digital rectal examination. Sera were drawn before biopsy and analyzed for tPSA, fPSA, cPSA and hK2 concentrations using standard methods (hK2 assay is for research use only, not for use in diagnostic procedures). The areas under the receiver operator characteristic curves were determined for each marker as well as biomarker combinations. Additionally, each parameter's specificity, positive and negative predictive values, and theoretical screening efficiency were assessed at or above the 95% sensitivity level. RESULTS A total of 43 (31.1%) men had prostate cancer by biopsy. While the AUC for %fPSA was statistically the highest (0.822, p <0.001), cPSA offered the highest specificity (31.6%) and positive predictive power (31.7%) of any of the tested biomarkers at comparable sensitivity (greater than 95%). The calculated efficiency of cPSA (51.4%) was also higher than the other markers. Nearly 20% of biopsies would be avoided using cPSA vs standard tPSA screening methods. CONCLUSIONS Comparing the major PSA isoforms and hK2, cPSA alone appears to offer superior diagnostic discrimination for cancer detection in a predominantly black population.
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Affiliation(s)
- B J Martin
- Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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Finne P, Finne R, Bangma C, Hugosson J, Hakama M, Auvinen A, Stenman UH. Algorithms based on prostate-specific antigen (PSA), free PSA, digital rectal examination and prostate volume reduce false-positive PSA results in prostate cancer screening. Int J Cancer 2004; 111:310-5. [PMID: 15197788 DOI: 10.1002/ijc.20250] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Our objective was to determine whether multivariate algorithms based on serum total PSA, the free proportion of PSA, age, digital rectal examination and prostate volume can reduce the rate of false-positive PSA results in prostate cancer screening more effectively than the proportion of free PSA alone at 95% sensitivity. A total of 1,775 consecutive 55- to 67-year-old men with a serum PSA of 4-10 microg/l in the European Randomized Study of Screening for Prostate Cancer were included. To predict the presence of cancer, multivariate algorithms were constructed using logistic regression (LR) and a multilayer perceptron neural network with Bayesian regularization (BR-MLP). A prospective setting was simulated by dividing the data set chronologically into one set for training and validation (67%, n = 1,183) and one test set (33%, n = 592). The diagnostic models were calibrated using the training set to obtain 95% sensitivity. When applied to the test set, the LR model, the BR-MLP model and the proportion of free PSA reached 92%, 87% and 94% sensitivity and reduced 29%, 36% and 22% of the false-positive PSA results, respectively. At a fixed sensitivity of 95% in the test set, the LR model eliminated more false-positive PSA results (22%) than the proportion of free PSA alone (17%) (p < 0.001), whereas the BR-MLP model did not (19%) (p = 0.178). The area under the ROC curve was larger for the LR model (0.764, p = 0.030) and the BR-MLP model (0.760, p = 0.049) than for the proportion of free PSA (0.718). A multivariate algorithm can be used to reduce unnecessary prostate biopsies in screening more effectively than the proportion of free PSA alone, but the algorithms will require updating when clinical practice develops with time.
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Affiliation(s)
- Patrik Finne
- Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland.
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Haese A, Graefen M, Huland H, Lilja H. Prostate-specific antigen and related isoforms in the diagnosis and management of prostate cancer. Curr Urol Rep 2004; 5:231-40. [PMID: 15161573 DOI: 10.1007/s11934-004-0042-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Despite its unparalleled merits for prostate cancer detection and staging, prostate-specific antigen (PSA) is not a marker for prostate cancer only, but also is expressed in benign conditions. For early detection, limitations of PSA are obvious. Its widespread use has led to an extensive amount of expensive and often unnecessary diagnostic procedures associated with significant morbidity. Total PSA derivatives may enhance the accuracy of prostate cancer diagnosis. The ratio of free-to-total PSA improves specificity while maintaining a high sensitivity for prostate cancer detection for men with a total PSA of 2.5 to 10 ng/mL. Human glandular kallikrein also has the potential to be a valuable tool in combination with total and free PSA for early diagnosis of prostate cancer. Complex PSA seems to be a reliable tool to improve specificity at high sensitivity levels in men with suspected prostate cancer (mainly in PSA levels below 4 ng/mL). Newly discovered isoforms of free PSA also may impact early detection of prostate cancer with encouraging preliminary results that warrant further clinical investigation.
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Affiliation(s)
- Alexander Haese
- Department of Urology, University Clinic Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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Abstract
The diagnosis, staging, and management of prostate cancer as we know it today is greatly dependent on our ability to measure serum prostate-specific antigen (PSA) concentration. Nevertheless, because serum PSA concentration, particularly when less than 10 ng/mL, reflects the presence of benign prostatic hyperplasia more often than cancer, there is a clear need for more specific prostate cancer markers. The most promising new markers for prostate cancer are the various molecular forms of free PSA. Mass spectrometry also is emerging as a potential tool in prostate cancer screening. Because it is unlikely that any one marker will have 100% sensitivity and specificity, as new serum markers are tested, nomograms that incorporate multiple independently predictive parameters for the detection of prostate cancer will become indispensable in our efforts to improve prostate cancer screening.
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Affiliation(s)
- Eduardo I Canto
- Scott Department of Urology, Baylor College of Medicine, The Baylor Prostate Center, 6560 Fannin Street, Suite 2100, Houston, TX 77030, USA
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Bangma CH, Wildhagen MF, Yurdakul G, Schröder FH, Blijenberg BG. The value of (−7, −5)pro-prostate-specific antigen and human kallikrein-2 as serum markers for grading prostate cancer. BJU Int 2004; 93:720-4. [PMID: 15049979 DOI: 10.1111/j.1464-410x.2003.04733.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To assess the value of the precursor form (-7,5pro) of prostate-specific antigen (PSA) and human kallikrein-2 (hK2) for detecting and grading prostate cancer, as better serum markers with improved specificity are needed in men with lower ranges of total (t)PSA. PATIENTS AND METHODS tPSA, free PSA (fPSA), the precursor (-7,5)proPSA and hK2 were measured in a subset of participants of the European Randomised Study of Screening of Prostate Cancer. In a pilot study, sera from 143 men biopsied but with no prostate cancer, 142 with BPH, and 146 with prostate cancer were analysed to determine the relative value of serum markers for differentiating between the groups. Then, in 141 men with prostate cancer who had a radical prostatectomy, these serum markers were related to the pathological grading to analyse their value as prognostic variables. RESULTS Levels of (-7,5)proPSA, hK2 and fPSA could be used to distinguish between BPH and cancer, but proPSA and hK2, alone or combined, did not improve the specificity of fPSA for discriminating BPH and cancer. There was also no correlation between these serum markers and pathological tumour grade. CONCLUSION The clinical effect of using (-7,5)proPSA or hK2 for detecting and grading prostate cancer remains limited.
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Affiliation(s)
- C H Bangma
- Department of Urology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
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Diamandis EP, Yousef GM, Olsson AY. An update on human and mouse glandular kallikreins. Clin Biochem 2004; 37:258-60. [PMID: 15003726 DOI: 10.1016/j.clinbiochem.2003.12.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Accepted: 12/24/2003] [Indexed: 10/26/2022]
Abstract
Human glandular kallikreins are secreted serine proteases, involved in many biological processes. Recently, the complete organization of the human and mouse genomic loci has been elucidated. These loci harbor the largest clusters of serine proteases within the human and mouse genomes. Mouse orthologs to all human kallikrein genes, except for KLK2 and KLK3 genes, have now been identified. Here, we describe an update of the genomic organization of these families in human and mouse, and provide some thoughts for future research directions.
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Affiliation(s)
- Eleftherios P Diamandis
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.
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Martin BJ, Finlay JA, Sterling K, Ward M, Lifsey D, Mercante D, Jainto JM, Martin L, Rayford W. Early detection of prostate cancer in African-American men through use of multiple biomarkers: human kallikrein 2 (hK2), prostate-specific antigen (PSA), and free PSA (fPSA). Prostate Cancer Prostatic Dis 2004; 7:132-7. [PMID: 15007379 DOI: 10.1038/sj.pcan.4500706] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent studies have reported enhanced prostate cancer detection in Caucasians with serum human glandular kallikrein 2 (hK2) in combination with total- (tPSA) and free-prostate-specific antigen (fPSA). The purpose of this study is to validate these findings in an African-American patient cohort. A total of 137 African-American men were found by routine screening to have tPSA levels above 2.5 ng/ml or an abnormal digital rectal examination. Sera were drawn prior to biopsy of the prostate and Hybritech PSA, FPSA and hK2 (for research use only, not for use in diagnostic procedures) concentrations were determined on Beckman Coulter's Access immunoanalyzer. These independent variables and the ratios of percent fPSA (%fPSA), hK2/tPSA, hK2/fPSA, and hK2*tPSA/fPSA were compared between cancer and non-cancer groups. In all, 49 of 137 men had prostate cancer. hK2 and its calculated ratios outperformed tPSA on receiver operator characteristic (ROC) analysis, but %fPSA had statistically the highest area under the curve (AUC) at 0.801. When restricting the analysis to only the tPSA range of 4.0-10 ng/ml, hK2/fPSA yielded the highest AUC (0.721). The ratio of hK2/fPSA was also found to increase the positive predictive value (PPV) of the %fPSA ranges less than 10 and 10-25%. %fPSA offered the best performance and highest specificity in prostate cancer detection in African-American males over the entire range of tPSA. hK2/fPSA may offer modest improvement in the tPSA range of 4.0-10 ng/ml. Furthermore, hK2/fPSA can enhance the PPV of low %fPSA values. Therefore, the use of multiple biomarkers may ultimately increase the specificity of prostate cancer screening in African-American men.
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Affiliation(s)
- B J Martin
- Louisiana State University Health Sciences Center, New Orleans, LA 70112-2822, USA
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Djavan B, Fong YK, Remzi M, Fakhari M, Marberger M. New Serum and Urinary Markers for Prostate Cancer Detection in the New Millennium. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.eursup.2004.02.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Haese A, Graefen M, Steuber T, Becker C, Noldus J, Erbersdobler A, Huland E, Huland H, Lilja H. Total and Gleason grade 4/5 cancer volumes are major contributors of human kallikrein 2, whereas free prostate specific antigen is largely contributed by benign gland volume in serum from patients with prostate cancer or benign prostatic biopsies. J Urol 2004; 170:2269-73. [PMID: 14634394 DOI: 10.1097/01.ju.0000095794.04551.0c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE We measured concentrations of human glandular kallikrein 2 (hK2), total prostate specific antigen (tPSA), free PSA (fPSA) and percent fPSA to evaluate their relationship to total prostate gland volume, benign prostatic hyperplasia (BPH) volume, total prostate cancer (PCa) volume (CaVol) and the volume of Gleason grades 4/5 cancer (CaVolGl4) in the serum of 256 patients with PCa undergoing radical retropubic prostatectomy and 185 with negative systematic sextant biopsies. MATERIALS AND METHODS Free and total PSA was measured using the Delfia Prostatus (Perkin-Elmer, Turku, Finland) total/free PSA assay and hK2 was measured using a research immunofluorometric assay. Transrectal ultrasound was used to determine total prostate and BPH volume. Total CaVol and CaVolGl4/5 were calculated using a volumetric program in specimens from 158 men with pT2a/b and 98 with pT3a or greater PCa. The Pearson correlation was performed after logarithmic conversion of PSA and hK2 levels. Benign gland, and pT2a/b and pT3a or greater PCa cases were subdivided into small vs large prostate gland volumes (42 cc or less vs greater than 42 cc). RESULTS Total prostate and BPH volumes correlated closely with free PSA (r = 0.64 to 0.65, p <0.0001) in 143 patients with negative biopsy and a prostate of greater than 42 cc. Correlations of hK2 and tPSA with total prostate and BPH volumes were weaker (r = 0.35 to 0.36 and 0.45 to 0.46, respectively). In pT2a/b and pT3a or greater PCa cases hK2 most closely correlated with CaVol (range 0.31 to 0.62, p = 0.0072 and <0.0001) and with CaVolGl4/5 (range 0.26 to 0.56, p = 0.021 and <0.0001, respectively). The tPSA level correlated significantly with CaVol and CaVolGl4/5 except in glands 42 cc or greater harboring pT2a/b PCa (p = 0.08). Free PSA correlated significantly with CaVolGl4/5 only in pT3a or greater PCa (p <0.05), and with CaVol in pT3a or greater PCa and in small prostates harboring pT2a/b PCa. CONCLUSIONS Large benign prostate gland volume affects fPSA more than tPSA in serum. In PCa hK2 more closely correlates with total cancer volume and high grade PCa volume compared with tPSA or fPSA.
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Affiliation(s)
- Alexander Haese
- Department of Urology, University Clinic Eppendorf, Hamburg, Germany.
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Becker C, Piironen T, Pettersson K, Hugosson J, Lilja H. Testing in Serum for Human Glandular Kallikrein 2, and Free and Total Prostate Specific Antigen in Biannual Screening for Prostate Cancer. J Urol 2003; 170:1169-74. [PMID: 14501718 DOI: 10.1097/01.ju.0000086640.19892.0b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE We investigated the value of serum measurements for glandular kallikrein 2 (hK2), and free (f) and total (t) prostate specific antigen (PSA) in a second round of biannual screening for prostate cancer. MATERIALS AND METHODS In 1995 to 1996, 5,853 of 9,811 randomly selected men in Göteborg, Sweden 50 to 66 years old had PSA measurements. Of 660 men 611 with tPSA 3 ng/ml or greater underwent biopsy and 145 had cancer. All were re-invited 2 years later for PSA testing, and 506 of 596 men with tPSA 3 ng/ml or greater underwent biopsy and 113 cancers were detected. We analyzed hK2, tPSA and fPSA in 423 of 453 (93%) men who underwent biopsy in 1997 to 1998 who were also screened in 1995 to 1996. RESULTS The 99 of 423 (23%) men who underwent biopsy diagnosed with prostate cancer in 1997 to 1998 had significantly different tPSA, percent fPSA and hK2 x tPSA/fPSA compared to the men with negative biopsies from 2 years earlier. The largest area under curve was obtained for hK2 x tPSA/fPSA in serum from 1995 to 1996 and from 1997 to 1998, but the difference was not significant compared to tPSA and percent fPSA. In serum from 1997 to 1998 measurements of hK2 x tPSA/fPSA gave significantly higher specificity than tPSA at 85% sensitivity, and significantly higher specificity than tPSA and percent fPSA at 70% to 75% sensitivity. In addition, levels of hK2 and hK2 x tPSA/fPSA manifested a significantly greater 2-year increase in men with cancer compared to those with benign biopsies. CONCLUSIONS In men with tPSA levels 3.0 ng/ml or greater who were not diagnosed with cancer during a first round of screening, hK2 measurements enhanced specificity compared to tPSA testing at moderately high sensitivity, and manifested a greater 2-year increase in men with cancer.
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Affiliation(s)
- Charlotte Becker
- Department of Clinical Chemistry, Lund University, University Hospital Malmö, Sweden.
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Nam RK, Zhang WW, Trachtenberg J, Diamandis E, Toi A, Emami M, Ho M, Sweet J, Evans A, Jewett MAS, Narod SA. Single nucleotide polymorphism of the human kallikrein-2 gene highly correlates with serum human kallikrein-2 levels and in combination enhances prostate cancer detection. J Clin Oncol 2003; 21:2312-9. [PMID: 12805332 DOI: 10.1200/jco.2003.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- Robert K Nam
- Division of Urology, 2075 Bayview Ave, MG-406, Toronto, Ontario, Canada, M4N 3M5.
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Haese A, Vaisanen V, Finlay JA, Pettersson K, Rittenhouse HG, Partin AW, Bruzek DJ, Sokoll LJ, Lilja H, Chan DW. Standardization of two immunoassays for human glandular kallikrein 2. Clin Chem 2003; 49:601-10. [PMID: 12651813 DOI: 10.1373/49.4.601] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Measurement of human kallikrein 2 (hK2) has improved early detection and staging of prostate cancer. However, reported concentrations of hK2 among currently used assays have not been standardized in any way. We compared two hK2 assays and five different recombinant hK2 variants (rhK2) and suggest a common calibrator as an important step and putative reference substance in hK2 assay standardization. METHODS We measured 146 sera by two hK2 assays, using assay-specific calibrators to assess the difference between the two assays. Serial dilutions of five rhK2 preparations were measured repeatedly, with one preparation assigned as calibrator and the others as unknowns to define which variant provided the closest match between the two assays. This rhK2 variant was used to recalibrate both assays. We measured hK2 concentrations in the same 146 patients to evaluate the change in the difference. RESULTS Use of assay-specific calibrators for comparison of the two assays yielded a Deming regression equation of: y = 0.789 (95% confidence interval, 0.674-0.922)x + 0.014 (0.004-0.025) micro g/L; R(2) = 0.667. Analysis of five rhK2 variants revealed that the enterokinase (ek)-rhK2 form provided the best match between both assays. Using the ek-rhK2 as a common calibrator, we observed a change in the slope of the regression curve to: y = 1.106 (0.872-1.340)x + 0.006 (-0.002 to 0.016) micro g/L; R(2) = 0.648, suggesting an increase in the mean estimate of agreement between the two assays. CONCLUSION Calibration with a common calibrator substantially increased agreement between the assays. The ek-rhK2 variant provided the best performance of all tested rhK2 variants and should undergo mass spectrometry and amino acid analysis for exact mass determination and value assignment to evaluate its potential as a reference material for immunoassays for hK2.
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Affiliation(s)
- Alexander Haese
- Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins University Medical Institutions, Baltimore, MD 21287, USA.
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Soukka T, Antonen K, Härmä H, Pelkkikangas AM, Huhtinen P, Lövgren T. Highly sensitive immunoassay of free prostate-specific antigen in serum using europium(III) nanoparticle label technology. Clin Chim Acta 2003; 328:45-58. [PMID: 12559598 DOI: 10.1016/s0009-8981(02)00376-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Recent proceedings in utilization of europium(III) chelate-dyed polystyrene nanoparticles as labels have combined the advantages of an enhanced monovalent binding affinity and a high specific activity of nanoparticle-antibody bioconjugate. Our objective was to evaluate the performance of the nanoparticle label technology with biological samples in an immunoassay of free prostate-specific antigen (PSA-F) using a standard microtitration well platform. METHODS Long-lifetime luminescent europium(III)-chelate nanoparticles, 107 nm in diameter, were coated with a PSA-F specific monoclonal antibody. The two-step noncompetitive immunoassay was performed in a microtitration well coated with a second monoclonal antibody. The signal of the surface-bound nanoparticle-antibody bioconjugates was measured directly from the bottom of the well using a standard time-resolved plate fluorometer. RESULTS The detection limit (mean + 2SD) of the nanoparticle-based PSA-F assay was 0.21 ng/l using a 20-microl sample volume. The assay response was linear up to 5 microg/l, and the functional sensitivity was approximately 0.5 ng/l. The within-run imprecision for spiked serum samples at concentrations 0.0005-0.5 microg/l was 6.4-21.8%, and the within-run and between-run imprecisions for serum samples at concentrations 0.2-2.5 microg/l were 3.4-7.2% and 4.4-7.6%, respectively. The concentrations obtained from serum samples correlated well with the reference immunoassay; slope = 1.018 +/- 0.018; intercept = 0.012 +/- 0.021 microg/l; S(y/x) = 0.112 microg/l; r = 0.993; n = 51. CONCLUSIONS The developed method demonstrated acceptable performance characteristics allowing clinical studies utilizing patient samples with extremely low concentrations of PSA-F. The present assay detected PSA-F in most of samples from prostatectomized men and in few samples from healthy women that were nondetectable according to the reference immunoassay.
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Affiliation(s)
- Tero Soukka
- Department of Biotechnology, University of Turku, Tykistökatu 6, FIN-20520 Turku, Finland.
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New Markers for Prostate Cancer Detection: What is on the Horizon? Prostate Cancer 2003. [DOI: 10.1016/b978-012286981-5/50059-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Jain S, Bhojwani AG, Mellon JK. Improving the utility of prostate specific antigen (PSA) in the diagnosis of prostate cancer: the use of PSA derivatives and novel markers. Postgrad Med J 2002; 78:646-50. [PMID: 12496317 PMCID: PMC1742550 DOI: 10.1136/pmj.78.925.646] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Prostate specific antigen (PSA) testing is now a routine part of the investigation of men with suspected prostate cancer. While a very useful test it still has its problems, in particular its lack of specificity means abnormal results are often caused by benign disease. This review describes the current problems with PSA testing in prostate cancer diagnosis and highlights potential ways in which these may be reduced.
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Affiliation(s)
- S Jain
- Division of Urology, University of Leicester, Leicester General Hospital, UK.
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46
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Strategies Combining Total and Percent Free Prostate Specific Antigen for Detecting Prostate Cancer: A Prospective Evaluation. J Urol 2002. [DOI: 10.1097/00005392-200206000-00019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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GANN PETERH, MA JING, CATALONA WILLIAMJ, STAMPFER MEIRJ. Strategies Combining Total and Percent Free Prostate Specific Antigen for Detecting Prostate Cancer: A Prospective Evaluation. J Urol 2002. [DOI: 10.1016/s0022-5347(05)64998-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- PETER H. GANN
- From the Department of Preventive Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, Illinois, Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School and Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, and Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - JING MA
- From the Department of Preventive Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, Illinois, Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School and Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, and Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - WILLIAM J. CATALONA
- From the Department of Preventive Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, Illinois, Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School and Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, and Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - MEIR J. STAMPFER
- From the Department of Preventive Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, Illinois, Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School and Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, and Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
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Réhault S, Brillard-Bourdet M, Bourgeois L, Frenette G, Juliano L, Gauthier F, Moreau T. Design of new and sensitive fluorogenic substrates for human kallikrein hK3 (prostate-specific antigen) derived from semenogelin sequences. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1596:55-62. [PMID: 11983421 DOI: 10.1016/s0167-4838(02)00204-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Human kallikrein hK3 (prostate-specific antigen) is a chymotrypsin-like serine protease which is widely used in the diagnosis of prostate cancer. Assays of the enzymatic activity of hK3 in extracellular fluids have been limited by a lack of sensitive synthetic substrates. This report describes the design of a series of internally quenched fluorescent peptides containing an amino acid sequence based on preferential hK3 cleavage sites in semenogelins. Those were identified by 2-D gel electrophoresis analysis and N-terminal sequencing of semenogelin fragments generated by ex vivo proteolysis in freshly ejaculated semen. These peptides were cleaved by hK3 at the C-terminal of certain tyrosyl or glutaminyl residues with k(cat)/K(m) values of 15000-60000 M(-1) s(-1). The substrate Abz-SSIYSQTEEQ-EDDnp was cleaved at the Tyr-Ser bond with a specificity constant k(cat)/K(m) of 60000 M(-1) s(-1), making it the best substrate for hK3 described to date.
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Affiliation(s)
- Sophie Réhault
- Laboratory of Enzymology and Protein Chemistry, INSERM EMI-U 00-10, University François Rabelais, 2bis Boulevard Tonnellé, 37032 Tours Cedex, France
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Abstract
BACKGROUND The evidence relating to the use of prostate-specific antigen (PSA) as a screening test is a highly controversial, as demonstrated by the lack of agreement among experts. There may be biases associated with various studies. ISSUES The main controversy is the relatively high prevalence of prostate cancer (PC) found at autopsy compared with the relatively low death rate from the disease. The lack of modifiable risk factors has led to early detection as a strategy to reduce mortality, as there is evidence for a significant burden of disease. Important issues are the accuracy of current screening tests, some attempts to improve on them, and whether there are good prognostic markers. The consequences of PSA testing (usually further testing including biopsy) and outcomes of treatment are presented in terms of mortality and morbidity; quality of life (QOL) must also be considered. Also important are the benefits from, and the difficulties associated with the "informed choice" approach to PSA screening. CONCLUSION There is evidence to suggest that biases can have a significant impact on the utility of PSA as a screening test for PC.
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Affiliation(s)
- Peter S Bunting
- Gamma-Dynacare Medical Laboratories, 115 Midair Court, Brampton, Ontario, Canada L6T 5M3.
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Becker C, Noldus J, Diamandis E, Lilja H. The role of molecular forms of prostate-specific antigen (PSA or hK3) and of human glandular kallikrein 2 (hK2) in the diagnosis and monitoring of prostate cancer and in extra-prostatic disease. Crit Rev Clin Lab Sci 2001; 38:357-99. [PMID: 11720279 DOI: 10.1080/20014091084236] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Prostate-specific antigen (PSA or hK3) is a glandular kallikrein with abundant expression in the prostate that is widely used to detect and monitor prostate cancer (PCa), although the serum level is frequently elevated also in benign and inflammatory prostatic diseases. PSA testing is useful for early detection of localized PCa and for the detection of disease recurrence after treatment. However, PSA has failed to accurately estimate cancer volume and preoperative staging. There is no PSA level in serum that definitively distinguishes men with benign conditions from those with prostate cancer, although PCa is rare in men with PSA levels in serum < 2.0 ng/ml. This prompted searches for enhancing parameters to combine with PSA testing, such as PSA density, PSA velocity, and age-specific reference ranges. Due to the protease structure, PSA occurs in different molecular forms in serum and their concentrations vary according to the type of prostatic disease. Human glandular kallikrein 2 (hK2) is very similar to PSA, but expressed at higher levels in prostate adenocarcinoma than in normal prostate epithelium. Blood testing for hK2 combined with different PSA forms improves discrimination of men with benign prostatic disease from those with prostate cancer. Many data have also been reported on the extra-prostatic expression of both PSA and hK2, and it is now believed that they may both have functions in tissues outside the prostate.
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Affiliation(s)
- C Becker
- Dept. of Clinical Chemistry, Lund University, Malmö University Hospital, Malmö, Sweden.
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