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The application of p2PSA% and prostate health index in prostate cancer detection: A prospective cohort in a Tertiary Medical Center. J Formos Med Assoc 2018; 118:260-267. [PMID: 29779925 DOI: 10.1016/j.jfma.2018.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/27/2018] [Accepted: 05/03/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND/PURPOSE Prostate specific antigen (PSA) with low specificity that causes unnecessary prostate biopsies increases clinical morbidities, psychological stress, and medical expenses. We aimed to test the accuracy and cutoff value of Prostate Health Index (PHI) in men for prostate cancer detection. METHODS We prospectively enrolled 213 men who underwent prostate biopsy with PSA≦10 ng/ml or abnormal findings on digital rectal examination. Total PSA (tPSA), free PSA (fPSA) and p2PSA levels were measured by serum samples before prostate biopsy. PHI was calculated as (p2PSA/fPSA) × √tPSA. Multivariable logistic regression analyses were used to predict the risk of cancer and detect clinically significant prostate cancer. RESULTS 33 (27.0%) patients were confirmed with the diagnoses of prostate cancer by prostate biopsy. The levels of p2PSA, %p2PSA, and PHI showed statistically significant differences between prostate cancer patients and non-cancer patients. %p2PSA and PHI had the highest area under the receiver operating characteristic curve (AUC) of 0.723 and 0.772 (both p < 0.001), respectively, predicting cancer detection at biopsy than other predictors (tPSA, fPSA, %fPSA, and PSA density (AUC: 0.544, 0.538, 0.593, and 0.664, respectively). In multivariable logistic regression, %p2PSA had a statistical significant odds ratio 8.51 (p = 0.003) and PHI had an odds ratio with marginal significance 4.18 (p = 0.06). CONCLUSION %p2PSA and PHI increased the diagnostic accuracy with significantly greater sensitivity and specificity than tPSA. We determined an optimal cut-off value of PHI among Taiwanese population. These findings support the usefulness in the decisional process of prostate biopsy.
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Hwang D, Yoon A, Kim S, Kim H, Chung J. Establishment of a mammalian expression system for recombinant [-2]proPSA and a specific antibody against the truncated leader peptide. Biotechnol Appl Biochem 2016; 64:327-336. [PMID: 26790760 DOI: 10.1002/bab.1481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/16/2016] [Indexed: 01/12/2023]
Abstract
A truncated precursor form of prostate-specific antigen (PSA), [-2]proPSA, is a well-known biomarker for prostate cancer. To develop a biomarker assay, highly purified [-2]proPSA is required as a standard reference and for generation of a specific antibody. In this study, we generated an efficient mammalian expression system for producing a recombinant [-2]proPSA-human kappa constant domain (Cκ ) fusion protein. N-terminal amino acid sequencing using Edman degradation demonstrated that over 95% of the recombinant protein produced is [-2]proPSA, thereby showing for the first time that recombinant [-2]proPSA can be produced as a major fraction. We also generated a recombinant chicken antibody specific to [-2]proPSA but not cross-reactive to recombinant [-7]proPSA-Cκ , [-5]proPSA-Cκ , and PSA purified from human seminal fluid in enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. Also, the recombinant chicken antibody reacted to recombinant [-2]proPSA protein bound to an anti-PSA antibody coated on the micrometer plate in a sandwich ELISA. All of these results suggest that the N-terminus of the [-2]proPSA-Cκ fusion protein resides on the exterior of the protein, thus allowing exposure to the antibody.
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Affiliation(s)
- Dobeen Hwang
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Aerin Yoon
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Soohyun Kim
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyori Kim
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Junho Chung
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
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Ayyıldız SN, Ayyıldız A. PSA, PSA derivatives, proPSA and prostate health index in the diagnosis of prostate cancer. Turk J Urol 2015; 40:82-8. [PMID: 26328156 DOI: 10.5152/tud.2014.94547] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/06/2014] [Indexed: 11/22/2022]
Abstract
Currently, prostate- specific antigen (PSA) is the most common oncological marker used for prostate cancer screening. However, high levels of PSA in benign prostatic hyperplasia and prostatitis decrease the specificity of PSA as a cancer marker. To increase the specificity of PSA, PSA derivatives and PSA kinetics have been used. However, these new techniques were not able to increase the diagnostic specificity for prostate cancer. Therefore, the search for new molecules and derivatives of PSA continues. With the aim of increasing the specificity of prostate cancer diagnosis, proPSA and the Prostate Health Index have been introduced. In this review, the roles of PSA, PSA derivatives, proPSA and the Prostate Health Index in Prostate Cancer diagnosis are examined.
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Affiliation(s)
- Sema Nur Ayyıldız
- Department of Biochemical, Ordu University Faculty of Medicine, Ordu, Turkey
| | - Ali Ayyıldız
- Department of Urology, Ordu University Faculty of Medicine, Ordu, Turkey
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Chen YT, Tuan LP, Chen HW, Wei IA, Chou MY, Chen HM, Tyan YC, Chen SF. Quantitative Analysis of Prostate Specific Antigen Isoforms Using Immunoprecipitation and Stable Isotope Labeling Mass Spectrometry. Anal Chem 2014; 87:545-53. [DOI: 10.1021/ac5033066] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yi-Ting Chen
- Department
of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
- Molecular
Medicine Research Center, Chang Gung University, Taoyuan 333, Taiwan
| | - Li-Ping Tuan
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677 Taiwan
| | - Hsiao-Wei Chen
- Molecular
Medicine Research Center, Chang Gung University, Taoyuan 333, Taiwan
| | - I-An Wei
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677 Taiwan
| | - Min-Yuan Chou
- Biomedical
Technology and Devices Research Laboratories, Industrial Technology Research Institute, Chutung 31040, Taiwan
| | - Han-Min Chen
- Department
of Life Science, Catholic Fu-Jen University, Taipei 24205, Taiwan
| | - Yu-Chang Tyan
- Department
of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Sung-Fang Chen
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677 Taiwan
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Mearini L, Ferri C, Lazzeri M, Bini V, Nunzi E, Fiorini D, Costantini E, Manasse GC, Porena M. Evaluation of Prostate-Specific Antigen Isoform p2PSA and Its Derivates, %p2PSA, Prostate Health Index and Prostate Dimension-Adjusted Related Index in the Detection of Prostate Cancer at First Biopsy: An Exploratory, Prospective Study. Urol Int 2014; 93:135-45. [DOI: 10.1159/000356240] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/07/2013] [Indexed: 11/19/2022]
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Sokoll LJ, Chan DW, Klee GG, Roberts WL, van Schaik RHN, Arockiasamy DA, Broyles DL, Carlson CM, Mizrahi IA, Pierson TB, Tam JE. Multi-center analytical performance evaluation of the Access Hybritech® p2PSA immunoassay. Clin Chim Acta 2012; 413:1279-83. [PMID: 22542565 DOI: 10.1016/j.cca.2012.04.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 01/13/2023]
Abstract
BACKGROUND Total PSA assays measure both complexed and non-complexed forms of PSA while free PSA assays only measure non-complexed forms. Free PSA is a mixture of isoforms including immature PSA (proPSA) with retained portions of the leader sequence (e.g. [-7], [-4], and [-2]proPSA) and nicked forms (BPSA). ProPSA isoforms in male sera have been associated with prostate cancer. This study characterized the analytical performance of a chemiluminescent immunoassay for [-2]proPSA. METHODS The Access Hybritech p2PSA assay is a sandwich immunoassay using an anti-[-2]proPSA monoclonal antibody attached to paramagnetic beads and an anti-PSA monoclonal antibody conjugated to alkaline phosphatase calibrated with recombinant [-2]proPSA. Analytical studies including sensitivity (CLSI EP17-A) and imprecision (CLSI EP5-A2) were performed. RESULTS The Access Hybritech p2PSA assay for [-2]proPSA had a dynamic range of 0.5 to 5000 pg/ml. The total CV of the assay was <7% for [-2]proPSA concentrations between 20 and 1000 pg/ml. The LOB was 0.50 pg/ml, LOD 0.69 pg/ml, and LOQ 3.23 pg/ml (20% CV). There was no hook effect up to 15,000 pg/ml. There was a <5% difference between calibrator and reagent lots and no interference from normal serum constituents. CONCLUSIONS The Access Hybritech p2PSA assay is a robust immunoassay for the measurement of serum [-2]proPSA.
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Affiliation(s)
- Lori J Sokoll
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, United States
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Catalona WJ, Partin AW, Sanda MG, Wei JT, Klee GG, Bangma CH, Slawin KM, Marks LS, Loeb S, Broyles DL, Shin SS, Cruz AB, Chan DW, Sokoll LJ, Roberts WL, van Schaik RHN, Mizrahi IA. A multicenter study of [-2]pro-prostate specific antigen combined with prostate specific antigen and free prostate specific antigen for prostate cancer detection in the 2.0 to 10.0 ng/ml prostate specific antigen range. J Urol 2011; 185:1650-5. [PMID: 21419439 PMCID: PMC3140702 DOI: 10.1016/j.juro.2010.12.032] [Citation(s) in RCA: 333] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Indexed: 01/12/2023]
Abstract
PURPOSE Prostate specific antigen and free prostate specific antigen have limited specificity to detect clinically significant, curable prostate cancer, leading to unnecessary biopsy, and detection and treatment of some indolent tumors. Specificity to detect clinically significant prostate cancer may be improved by [-2]pro-prostate specific antigen. We evaluated [-2]pro-prostate specific antigen, free prostate specific antigen and prostate specific antigen using the formula, ([-2]pro-prostate specific antigen/free prostate specific antigen × prostate specific antigen(1/2)) to enhance specificity to detect overall and high grade prostate cancer. MATERIALS AND METHODS We enrolled 892 men with no history of prostate cancer, normal rectal examination, prostate specific antigen 2 to 10 ng/ml and 6-core or greater prostate biopsy in a prospective multi-institutional trial. We examined the relationship of serum prostate specific antigen, free-to-total prostate specific antigen and the prostate health index with biopsy results. Primary end points were specificity and AUC using the prostate health index to detect overall and Gleason 7 or greater prostate cancer on biopsy compared with those of free-to-total prostate specific antigen. RESULTS In the 2 to 10 ng/ml prostate specific antigen range at 80% to 95% sensitivity the specificity and AUC (0.703) of the prostate health index exceeded those of prostate specific antigen and free-to-total prostate specific antigen. An increasing prostate health index was associated with a 4.7-fold increased risk of prostate cancer and a 1.61-fold increased risk of Gleason score greater than or equal to 4 + 3 = 7 disease on biopsy. The AUC of the index exceeded that of free-to-total prostate specific antigen (0.724 vs 0.670) to discriminate prostate cancer with Gleason 4 or greater + 3 from lower grade disease or negative biopsy. Prostate health index results were not associated with age and prostate volume. CONCLUSIONS The prostate health index may be useful in prostate cancer screening to decrease unnecessary biopsy in men 50 years old or older with prostate specific antigen 2 to 10 ng/ml and negative digital rectal examination with minimal loss in sensitivity.
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Affiliation(s)
- William J Catalona
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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Liang Y, Ankerst DP, Ketchum NS, Ercole B, Shah G, Shaughnessy JD, Leach RJ, Thompson IM. Prospective evaluation of operating characteristics of prostate cancer detection biomarkers. J Urol 2010; 185:104-10. [PMID: 21074193 DOI: 10.1016/j.juro.2010.08.088] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE We assessed the independent predictive values of the serum markers free prostate specific antigen, proenzyme prostate specific antigen, neuroendocrine marker and Dickkopf-1 compared to serum prostate specific antigen and other standard risk factors for early prostate cancer detection. MATERIALS AND METHODS From the prospectively collected SABOR cohort 250 prostate cancer cases, and 250 mean age matched and proportion of African-American race/ethnicity matched controls were selected who had a prior available prostate specific antigen and digital rectal examination. Serum samples were obtained, and free prostate specific antigen, [-2]proenzyme prostate specific antigen, Dickkopf-1 and neuroendocrine marker were measured. AUC, sensitivities and specificities were calculated, and multivariable logistic regression was used to assess the independent predictive value compared to prostate specific antigen, digital rectal examination, family history, prior biopsy history, race/ethnicity and age. RESULTS The AUCs (95% CI) were 0.76 (0.71, 0.8) for free prostate specific antigen, 0.72 (0.67, 0.76) for [-2]proenzyme prostate specific antigen, 0.76 (0.72, 0.8) for %free prostate specific antigen, 0.61 (0.56, 0.66) for %[-2]proenzyme prostate specific antigen, 0.73 (0.68, 0.77) for prostate health index, 0.53 (0.48, 0.58) for Dickkopf-1 and 0.53 (0.48, 0.59) for neuroendocrine marker. In the 2 to 10 ng/ml prostate specific antigen range the AUCs (95% CI) were 0.58 (0.49, 0.67) for free prostate specific antigen, 0.53 (0.44, 0.62) for [-2]proenzyme prostate specific antigen, 0.67 (0.59, 0.75) for %free prostate specific antigen, 0.57 (0.49, 0.65) for %[-2]proenzyme prostate specific antigen and 0.59 (0.51, 0.67) for phi. Only %free prostate specific antigen retained independent predictive value compared to the traditional risk factors. CONCLUSIONS Free prostate specific antigen retained independent diagnostic usefulness for prostate cancers detected through prostate specific antigen and digital rectal examination screening. Prostate specific antigen isoforms are highly correlated with prostate specific antigen. Future research is needed to identify new markers associated with prostate cancer through different mechanisms.
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Affiliation(s)
- Yuanyuan Liang
- Department of Urology, University of Texas Health Science Center, San Antonio, Texas, USA.
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Pre-analytical in-vitro stability of [-2]proPSA in blood and serum. Clin Biochem 2010; 43:926-8. [PMID: 20450900 DOI: 10.1016/j.clinbiochem.2010.04.062] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Revised: 04/12/2010] [Accepted: 04/15/2010] [Indexed: 11/22/2022]
Abstract
OBJECTIVES [-2]proPSA may discriminate prostate cancer from benign biopsy results. We characterized the pre-analytical stability of [-2]proPSA. DESIGN AND METHODS 22 volunteers, total PSA of 4.5-19.3microg/L, had blood drawn simultaneously. Baseline measurements were performed and samples were stored under various conditions prior to measurements. Freeze-thaw cycles were performed. [-2]proPSA was measured with the p2PSA automated research use only immunoassay on the Access analyzer. RESULTS Mean [-2]proPSA increases with clotting time, exceeding 10% change in recovery after 3h. In serum, [-2]proPSA values decline over time under investigated storage conditions. Serum samples kept frozen show less than 10% variation in recoveries over the course of 2 freeze-thaw cycles. CONCLUSIONS For proper measurement of [-2]proPSA, blood samples should be centrifuged within 3h of blood draw. Serum may be stored at RT or refrigerated (+4 degrees C) for a maximum of 48h and should be frozen if stored for a longer period. Two freeze-thaw cycles have no effect on [-2]proPSA stability.
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10
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Sokoll LJ, Sanda MG, Feng Z, Kagan J, Mizrahi IA, Broyles DL, Partin AW, Srivastava S, Thompson IM, Wei JT, Zhang Z, Chan DW. A prospective, multicenter, National Cancer Institute Early Detection Research Network study of [-2]proPSA: improving prostate cancer detection and correlating with cancer aggressiveness. Cancer Epidemiol Biomarkers Prev 2010; 19:1193-200. [PMID: 20447916 PMCID: PMC2867076 DOI: 10.1158/1055-9965.epi-10-0007] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The free prostate-specific antigen (PSA) isoform, [-2]proPSA, has been shown to be associated with prostate cancer. The study objective was to characterize the clinical utility of serum [-2]proPSA for prostate cancer detection and assess its association with aggressive disease. METHODS From among 669 subjects in a prospective prostate cancer detection study at four National Cancer Institute Early Detection Research Network clinical validation centers, 566 were eligible. Serum PSA, free PSA, and [-2]proPSA were measured (Beckman Coulter Access 2 Analyzer). RESULTS Two hundred and forty-five (43%) of the 566 participants had prostate cancer on biopsy. At 70% specificity, the sensitivity of %[-2]proPSA ([-2]proPSA/fPSA) was 54% [95% confidence interval (CI), 48-61%; null hypothesis, 40%]. Including %[-2]proPSA in a multivariate prediction model incorporating PSA and %fPSA improved the performance (P<0.01). In the 2 to 4 ng/mL PSA range, %[-2]proPSA outperformed %fPSA (receiver operator characteristic-areas under the curve, 0.73 versus 0.61; P=0.01). At 80% sensitivity, %[-2]proPSA had significantly higher specificity (51.6%; 95% CI, 41.2-61.8%) than PSA (29.9%; 95% CI, 21.0-40.0%) and %fPSA (28.9%; 95% CI, 20.1-39.0%). In the 2 to 10 ng/mL PSA range, a multivariate model had significant improvement (area under the curve, 0.76) over individual PSA forms (P<0.01 to <0.0001). At 80% sensitivity, the specificity of %[-2]proPSA (44.9%; 95% CI, 38.4-51.5%) was significantly higher than PSA (30.8%; 95% CI, 24.9-37.1%) and relatively higher than %fPSA (34.6%; 95% CI, 28.5-41.4%). %[-2]proPSA increased with increasing Gleason score (P<0.001) and was higher in aggressive cancers (P=0.03). CONCLUSIONS In this prospective study, %[-2]proPSA showed potential clinical utility for improving prostate cancer detection and was related to the risk of aggressive disease. IMPACT The addition of %[-2]proPSA could affect the early detection of prostate cancer.
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Affiliation(s)
- Lori J Sokoll
- Department of Pathology, Johns Hopkins Medical Institutions, 600 North Wolfe Street, Meyer B-125, Baltimore, MD 21287, USA.
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11
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[-2]Proenzyme prostate specific antigen is more accurate than total and free prostate specific antigen in differentiating prostate cancer from benign disease in a prospective prostate cancer screening study. J Urol 2010; 183:1355-9. [PMID: 20171670 DOI: 10.1016/j.juro.2009.12.056] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Indexed: 11/22/2022]
Abstract
PURPOSE Due to the limited specificity of prostate specific antigen for prostate cancer screening, there is an ongoing search for adjunctive biomarkers. Retrospective studies have suggested that an isoform of proenzyme prostate specific antigen called [-2]proenzyme prostate specific antigen may enhance the specificity of prostate specific antigen based screening. We examined the usefulness of this isoform in a prospective prostate cancer screening study. MATERIALS AND METHODS From a population of 2,034 men undergoing prostate cancer screening we examined the relationship between the measurement of the [-2]isoform of proenzyme prostate specific antigen (p2PSA) and prostate cancer detection. Specifically we compared the usefulness of total prostate specific antigen, the ratio of free-to-total prostate specific antigen, the ratio of p2PSA-to-free prostate specific antigen, and a formula combining prostate specific antigen, free prostate specific antigen and p2PSA (the Beckman Coulter prostate health index or phi) to predict prostate cancer in men from the study undergoing prostate biopsy with a prostate specific antigen of 2.5 to 10 ng/ml and nonsuspicious digital rectal examination. RESULTS Despite similar total prostate specific antigen (p = 0.88), percent free prostate specific antigen (p = 0.02) and %p2PSA (p = 0.0006) distinguished between positive and negative biopsy results. On ROC analysis %p2PSA (AUC 0.76) outperformed prostate specific antigen (AUC 0.50) and percent free prostate specific antigen (AUC 0.68) for differentiating between prostate cancer and benign disease. Setting the sensitivity at 88.5%, p2PSA led to a substantial improvement in specificity as well as positive and negative predictive values. The Beckman Coulter prostate health index (AUC 0.77) had the best overall performance characteristics. CONCLUSIONS This is the first prospective study to our knowledge to demonstrate that p2PSA provides improved discrimination between prostate cancer and benign disease in screened men with a prostate specific antigen of 2.5 to 10 ng/ml and a negative digital rectal examination.
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Jansen FH, van Schaik RHN, Kurstjens J, Horninger W, Klocker H, Bektic J, Wildhagen MF, Roobol MJ, Bangma CH, Bartsch G. Prostate-specific antigen (PSA) isoform p2PSA in combination with total PSA and free PSA improves diagnostic accuracy in prostate cancer detection. Eur Urol 2010; 57:921-7. [PMID: 20189711 DOI: 10.1016/j.eururo.2010.02.003] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 02/03/2010] [Indexed: 11/26/2022]
Abstract
BACKGROUND Novel markers for prostate cancer (PCa) detection are needed. Total prostate-specific antigen (tPSA) and percent free prostate-specific antigen (%fPSA=tPSA/fPSA) lack diagnostic specificity. OBJECTIVE To evaluate the use of prostate-specific antigen (PSA) isoforms p2PSA and benign prostatic hyperplasia-associated PSA (BPHA). DESIGN, SETTING, AND PARTICIPANTS Our study included 405 serum samples from the Rotterdam arm of the European Randomised Study of Screening for Prostate Cancer and 351 samples from the Urology Department of Innsbruck Medical University. MEASUREMENTS BPHA, tPSA, fPSA, and p2PSA levels were measured by Beckman-Coulter Access Immunoassay. In addition, the Beckman Coulter Prostate Health Index was calculated: phi=(p2PSA/fPSA)×√(tPSA). RESULTS AND LIMITATIONS The p2PSA and phi levels differed significantly between men with and without PCa. No difference in BPHA levels was observed. The highest PCa predictive value in both cohorts was achieved by phi with areas under the curve (AUCs) of 0.750 and 0.709, a significant increase compared to tPSA (AUC: 0.585 and 0.534) and %fPSA (AUC: 0.675 and 0.576). Also, %p2PSA (p2PSA/fPSA) showed significantly higher AUCs compared to tPSA and %fPSA (AUC: 0.716 and 0.695, respectively). At 95% and 90% sensitivity, the specificities of phi were 23% and 31% compared to 10% and 8% for tPSA, respectively. In both cohorts, multivariate analysis showed a significant increase in PCa predictive value after addition of p2PSA to a model consisting of tPSA and fPSA (increase in AUC from 0.675 to 0.755 and from 0.581 to 0.697, respectively). Additionally, the specificity at 95% sensitivity increased from 8% to 24% and 7% to 23%, respectively. Furthermore, %p2PSA, phi, and the model consisting of tPSA and fPSA with or without the addition of p2PSA missed the least of the tumours with a biopsy or pathologic Gleason score ≥7 at 95% and 90% sensitivity. CONCLUSIONS This study shows significant increases in PCa predictive value and specificity of phi and %p2PSA compared to tPSA and %fPSA. p2PSA has limited additional value in identifying aggressive PCa (Gleason score ≥7).
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Affiliation(s)
- Flip H Jansen
- Department of Urology, Erasmus MC, Rotterdam, The Netherlands.
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13
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Stephan C, Cammann H, Deger S, Schrader M, Meyer HA, Miller K, Lein M, Jung K. Benign prostatic hyperplasia-associated free prostate-specific antigen improves detection of prostate cancer in an artificial neural network. Urology 2009; 74:873-7. [PMID: 19476981 DOI: 10.1016/j.urology.2009.02.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Revised: 02/18/2009] [Accepted: 02/21/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To show discriminative power between patients with prostate cancer (PCa) and those with "no evidence of malignancy" using "benign" prostate-specific antigen (bPSA) and the new automated Access benign prostatic hyperplasia-associated (BPHA) research assay within a percent free PSA (%fPSA)-based artificial neural network (ANN) model. METHODS The sera from 287 patients with PCa and 254 patients with no evidence of malignancy were measured using the BPHA, total PSA (tPSA), and fPSA assays with Access immunoassay technology, with a 0-10 ng/mL tPSA range. Two ANN models with Bayesian regularization and leave-one-out validation using the 4 input parameters of tPSA, %fPSA, age, and prostate volume and 1 containing BPHA/tPSA were constructed and compared by receiver operating characteristic curve analysis. RESULTS The BPHA/tPSA-based ANN reached the significant greatest area under the receiver operating characteristic curve (AUC 0.81; P = .0004 and P = .0024) and best specificity (53.9% and 44.5%) compared with the ANN without BPHA/tPSA (AUC 0.77; specificity 50% and 40.6%) and %fPSA (AUC 0.77; specificity 40.9% and 27.2%) at 90% and 95% sensitivity, respectively. The AUCs for tPSA (0.58), BPHA (0.55), BPHA/fPSA (0.51), prostate volume (0.69), and BPHA/tPSA (0.69) were significantly lower. CONCLUSIONS Although BPHA as single marker or ratio to tPSA did not improve the diagnostic performance of %fPSA or tPSA, the incorporation of BPHA/tPSA into an ANN model increased the specificity compared with %fPSA by 13% and 17% at 90% and 95% sensitivity, respectively. Thus, the automated BPHA research assay might improve PCa detection when incorporating this new marker into an ANN.
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Affiliation(s)
- Carsten Stephan
- Department of Urology and Institute of Medical Informatics, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Proteomic analysis of conditioned media from glucose responsive and glucose non-responsive phenotypes reveals a panel of secreted proteins associated with beta cell dysfunction. Electrophoresis 2009; 29:4141-9. [PMID: 18924105 DOI: 10.1002/elps.200800152] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Media conditioned by dysfunctioning pancreatic beta cells offer an excellent source of potential protein markers associated with this phenotype. Proteins identified from cell culture model systems are often found to be of importance clinically. Previous work by us and others have shown that low-passage MIN-6 cells (MIN-6(L)) respond to changes in glucose concentrations, producing an approximately 5.5-fold glucose-stimulated insulin secretion (GSIS) in response to 26.7 mmol/L, compared with 3.3 mmol/L, glucose. After continuous culture or high-passage (MIN-(H)), this GSIS was no longer present and thus represents an excellent model system for investigating beta cell dysfunction. Employing 2-D difference gel electrophoresis and mass spectrometry a panel of protein markers were identified in conditioned media (CM) from MIN-6(L) and MIN-6(H) beta cells. These proteins, including secretogranin II, secretogranin III and transthyretin, are associated with secretory granule biogenesis and were found to have substantially increased levels in the CM from the non-responsive high-passage MIN-6 beta cells. A panel of protein markers found to have increased abundance levels in CM from MIN-6(H) compared with MIN-6(L) beta cells may have the potential to be used clinically for assessing beta cell function and to monitor the effects of specific therapeutics.
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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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Sokoll LJ, Wang Y, Feng Z, Kagan J, Partin AW, Sanda MG, Thompson IM, Chan DW. [-2]proenzyme prostate specific antigen for prostate cancer detection: a national cancer institute early detection research network validation study. J Urol 2008; 180:539-43; discussion 543. [PMID: 18550118 DOI: 10.1016/j.juro.2008.04.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Indexed: 10/22/2022]
Abstract
PURPOSE This study evaluated the [-2]proenzyme prostate specific antigen serum marker using a blinded reference specimen set from 3 National Cancer Institute Early Detection Research Network centers from men with an indication for prostate biopsy. MATERIALS AND METHODS Serum was collected before biopsy from 123 men with no prior biopsy or prostate cancer history. Specimens (cancer cases 51%, noncancer controls 49%) were selected equally from the 3 sites, and analyzed for prostate specific antigen, free prostate specific antigen, [-2]proenzyme prostate specific antigen, benign prostate specific antigen and testosterone (Beckman Coulter ACCESS(R) analyzer). RESULTS There was no difference in total prostate specific antigen concentrations (noncancer 6.80 +/- 5.20 ng/ml, cancer 6.94 +/- 5.12 ng/ml) among the groups. Overall %[-2]proenzyme prostate specific antigen had the greatest area under the curve (AUC 0.69) followed by percent free prostate specific antigen (AUC 0.61). For %[-2]proenzyme prostate specific antigen maximal sensitivity was 60% and specificity was 70%. A logistic regression model combining prostate specific antigen, benign prostate specific antigen, percent free prostate specific antigen, %[-2]proenzyme prostate specific antigen, [-2]proenzyme prostate specific antigen/benign prostate specific antigen and testosterone had an AUC of 0.73. In the 2 to 10 ng/ml prostate specific antigen range %[-2]proenzyme prostate specific antigen and the model had the largest AUC (0.73). The AUC for percent free prostate specific antigen was 0.53. Specificities for %[-2]proenzyme prostate specific antigen, the logistic regression model and percent free prostate specific antigen at 90% sensitivity were 41%, 32% and 18%, and at 95% sensitivity were 31%, 26% and 16%, respectively. CONCLUSIONS %[-2]proenzyme prostate specific antigen was the best predictor of prostate cancer detection compared to percent free prostate specific antigen, particularly in the 2 to 10 ng/ml total prostate specific antigen range. These findings provide a rationale for broader validation studies to determine whether %[-2]proenzyme prostate specific antigen alone can replace other molecular prostate specific antigen assays (such as percent free prostate specific antigen) for improving the accuracy of prostate cancer early detection. These findings also support the usefulness of well characterized, carefully collected reference sets to evaluate new biomarkers.
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Affiliation(s)
- Lori J Sokoll
- Departments of Pathology and Urology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
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Levitt JM, Slawin KM. Prostate-specific antigen and prostate-specific antigen derivatives as predictors of benign prostatic hyperplasia progression. Curr Urol Rep 2008; 8:269-74. [DOI: 10.1007/s11934-007-0072-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Pampalakis G, Scorilas A, Sotiropoulou G. Novel splice variants of prostate-specific antigen and applications in diagnosis of prostate cancer. Clin Biochem 2008; 41:591-7. [PMID: 18222179 DOI: 10.1016/j.clinbiochem.2007.12.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 12/06/2007] [Accepted: 12/29/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVES We aimed to identify novel splice variants of prostate-specific antigen/or human kallikrein 3 (PSA/KLK3), the most widely used serum biomarker for case-finding, screening and monitoring of prostate cancer. DESIGN AND METHODS The full-length sequences of splice variants were assembled as contigs from human ESTs that displayed homology to the cDNA sequence encoding PSA. Expression of variants in clinical samples was analyzed by semi-quantitative RT-PCR. RESULTS EST database mining led to the identification of seven previously unidentified splice variants encoding PSA-like proteins that are predicted to contain epitope sequences recognized by PSA-specific antibodies, therefore, expression of these isoforms may affect the amount of total PSA measured by established immunoassays. Analysis of the differential expression profile of isoform PSA-SV5 in patients with benign prostate hyperplasia and prostate cancer showed that it is specifically expressed in prostate cancers. CONCLUSIONS A novel splice variant of PSA was identified, PSA-SV5, that may be exploited in clinical diagnosis to distinguish prostate cancer from benign prostate hyperplasia.
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