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Kaufmann B, Pellegrino P, Zuluaga L, Ben-David R, Müntener M, Keller EX, Spanaus K, von Eckardstein A, Gorin MA, Poyet C. Interassay Variability and Clinical Implications of Five Different Prostate-specific Antigen Assays. EUR UROL SUPPL 2024; 63:4-12. [PMID: 38558765 PMCID: PMC10981008 DOI: 10.1016/j.euros.2024.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
Background and objective Prostate-specific antigen (PSA) remains a critical marker for prostate cancer (PCa) detection and monitoring. Recognising historical variability in PSA assays and the evolution of assay technology and calibration, this study aims to reassess interassay variability using the latest generation of five assays in a contemporary cohort of men undergoing prostate biopsy. Methods Five different commercially available PSA assays were tested in a blood sample of 76 men before undergoing a prostate biopsy. Total PSA (tPSA) and free-to-total PSA ratio (%fPSA) were compared across assays, using Roche (Basel, Switzerland) as the benchmark, and correlated with biopsy outcome to analyse the impact on PCa diagnosis. The statistical analysis included Passing-Bablok regression and Bland-Altman plots, with a p value threshold of <0.05 for significance. Key findings and limitations Among the 76 men, 28 (36.8%) were diagnosed with significant PCa (defined as International Society of Urological Pathology grade ≥2). A high correlation was observed between tPSA and %fPSA values among the different PSA assays tested (r2 ≥ 0.9). The Passing-Bablok analysis showed that tPSA results varied substantially among the assays, with slopes ranging between 0.78 and 1.04. Compared with the tPSA of Roche, tPSA values were on average 20.7% lower by Beckman (Oststeinbeck, Germany), 15.2% lower by Abbott (Chicago, IL, USA), 6.1% lower by Diasorin (Saluggia, Italy), and 9.6% higher by Brahms (Hennigsdorf, Germany; p < 0.001 for all). The %fPSA values by Abbott and Brahms were higher at 15.7% and 10.6%, respectively (p < 0.001), while the Beckman and Diasorin values had minimal differences of -0.3% and 2.3%, respectively (p > 0.05). The variability across assays would have resulted in discrepancies in both the sensitivity and the specificity for tPSA and %fPSA by at least 14%, depending on the cut-offs applied. Conclusions and clinical implications Despite the use of the latest PSA assays, relevant variability of tPSA and %fPSA results can be observed among different assays. There is an urgent need for standardised calibration methods and greater awareness among practitioners concerning interassay variability. Clinicians should acknowledge that clinically relevant thresholds may depend on the specific PSA assay and that ideally the same assay is applied over time for better clinical decision-making. Patient summary Prostate-specific antigen (PSA) is a critical marker for prostate cancer (PCa) detection and monitoring. However, significant variations were observed in the results of the latest PSA assays. Thus, standardised calibration methods and greater awareness among practitioners concerning interassay variability are needed.
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Affiliation(s)
- Basil Kaufmann
- Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Paloma Pellegrino
- Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Laura Zuluaga
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Reuben Ben-David
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Michael Müntener
- Department of Urology, Municipal Hospital of Zurich, Zurich, Switzerland
| | - Etienne X. Keller
- Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Katharina Spanaus
- Institute for Clinical Chemistry, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Arnold von Eckardstein
- Institute for Clinical Chemistry, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Michael A. Gorin
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Cédric Poyet
- Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Ferraro S, Biganzoli EM, Plebani M. Reply to: Spurious results for total and free prostate-specific antigen (PSA); sometimes really "a riddle wrapped in a mystery inside an enigma". Clin Chem Lab Med 2022; 60:e95-e96. [PMID: 35258238 DOI: 10.1515/cclm-2022-0088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 11/15/2022]
Affiliation(s)
- Simona Ferraro
- Endocrinology Laboratory Unit, "Luigi Sacco" University Hospital, Milan, Italy
| | - Elia Mario Biganzoli
- Medical Statistics Unit, Department of Biomedical and Clinical Sciences L. Sacco, "Luigi Sacco" University Hospital, Università degli Studi di Milano, Milan, Italy
| | - Mario Plebani
- Department of Medicine-DIMED, University of Padova, Padova, Italy
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Ferraro S, Bussetti M, Rizzardi S, Braga F, Panteghini M. Verification of Harmonization of Serum Total and Free Prostate-Specific Antigen (PSA) Measurements and Implications for Medical Decisions. Clin Chem 2021; 67:543-553. [PMID: 33674839 DOI: 10.1093/clinchem/hvaa268] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/08/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND Previous studies have shown that the harmonization of prostate-specific antigen (PSA) assays remained limited even after the introduction of WHO International Standards. This information needs updating for current measuring systems (MS) and reevaluation according to established analytical performance specifications (APS) and the characteristics of antibodies used. METHODS Total (tPSA) and free (fPSA) PSA were measured in 135 and 137 native serum samples, respectively, by Abbott Alinity i, Beckman Access Dxl, Roche Cobas e801, and Siemens Atellica IM MSs. Passing-Bablok regression and difference plots were used to compare results from each MS to the all-method median values. Agreement among methods was evaluated against APS for bias derived from biological variation of the 2 measurands. RESULTS The median interassay CV for tPSA MSs (11.5%; 25-75th percentiles, 9.2-13.4) fulfilled the minimum APS goal for intermethod bias (15.9%), while the interassay CV for fPSA did not [20.4% (25-75th percentiles, 18.4-22.7) vs goal 17.6%]. Considering the all-method median value of each sample as reference, all tPSA MSs exhibited a mean percentage bias within the minimum goal. On the other hand, Alinity (+21.3%) and Access (-24.2%) were out of the minimum bias goal for fPSA, the disagreement explained only in minimal part by the heterogeneity of employed antibodies. CONCLUSIONS The harmonization among tPSA MSs is acceptable only when minimum APS are applied and necessitates further improvement. The marked disagreement among fPSA MSs questions the use of fPSA as a second-level test for biopsy referral.
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Affiliation(s)
- Simona Ferraro
- Unità Operativa Complessa di Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Marco Bussetti
- Unità Operativa Complessa di Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Sara Rizzardi
- Unità Operativa Laboratorio Analisi Chimico Cliniche e Microbiologiche, ASST Cremona, Cremona, Italy
| | - Federica Braga
- Unità Operativa Complessa di Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy.,Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | - Mauro Panteghini
- Unità Operativa Complessa di Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy.,Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
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4
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Ferraro S, Bussetti M, Panteghini M. Serum Prostate-Specific Antigen Testing for Early Detection of Prostate Cancer: Managing the Gap between Clinical and Laboratory Practice. Clin Chem 2021; 67:602-609. [PMID: 33619518 DOI: 10.1093/clinchem/hvab002] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/21/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Current clinical practice guidelines (CPGs) for early detection of prostate cancer recommend for clinical decision-making a personalized prostate-specific antigen (PSA)-based management to improve the risk-benefit ratio of the screening strategy. Some important critical issues regarding the PSA determination in the clinical framework are, however, still neglected in current guidelines and a major focus of recommendations on those aspects would be needed to improve their effectiveness. CONTENT Evidence sources in the available literature concerning the interchangeability of total PSA results measured with different commercial methods were critically appraised. We discuss how the heterogeneity of the measurand, the intermethod bias, and the design and selectivity of immunoassays may affect the diagnostic accuracy of selected PSA thresholds, and how knowledge of the analytical characteristics of assays in service, such as the recognized PSA circulating forms and the cross-reactivity with PSA homologs, is basic for improving both clinical decision-making in cancer screening and the reliability of the clinical interpretation of results at the individual level. SUMMARY Current CPGs ignore the poor interchangeability of PSA results obtained from different assays and the substantial role of laboratory issues in clinical performance of PSA testing. Involved stakeholders should contribute to fill the existing gap by: (a) preparing commutable reference materials for immunoassay calibration; (b) providing analytical characteristics that may explain the different performance of assays; (c) deriving outcome-based analytical performance specifications for PSA measurement; and (d) giving more focus on laboratory items when CPGs are prepared.
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Affiliation(s)
- Simona Ferraro
- Department of Biomedical and Clinical Sciences, 'Luigi Sacco', University of Milan, and Clinical Pathology Unit, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Marco Bussetti
- Department of Biomedical and Clinical Sciences, 'Luigi Sacco', University of Milan, and Clinical Pathology Unit, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Mauro Panteghini
- Department of Biomedical and Clinical Sciences, 'Luigi Sacco', University of Milan, and Clinical Pathology Unit, ASST Fatebenefratelli-Sacco, Milan, Italy
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Chen R, Xiao Y, Liu H, Fang L, Liu J, Ruan X, Chen B, Luan T. Lab-on-Membrane Platform Coupled with Paper Spray Ionization for Analysis of Prostate-Specific Antigen in Clinical Settings. Anal Chem 2020; 92:13298-13304. [PMID: 32845627 DOI: 10.1021/acs.analchem.0c02554] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The analysis of protein antigens as biomarkers in clinical samples is particularly helpful for the early diagnosis of diseases. However, this is difficult to accomplish owing to the presence of the antigens in trace amounts as well as the complexity of the matrixes in clinical samples. In this study, a lab-on-membrane platform that can be combined with paper spray ionization mass spectrometry was developed for the in situ high-throughput sensitive detection of the prostate-specific antigen (PSA). The sensitivity of the proposed platform was enhanced via two strategies: (1) the synthesis of a biotin-streptavidin scaffold caused an increase in the capturing efficiency of PSA by a factor of 5 and (2) the immobilization of a large number of mass tag molecules on the gold nanoparticles allowed for the amplification of the mass spectrometry signals. The limit of detection was approximately 3.0 pg mL-1. The selectivity to PSA was guaranteed by using an antibody-aptamer pairing sandwich immunoassay, and PSA detection was unaffected even when other protein antigens (carcinoembryonic antigen and carbohydrate antigen 125) were present. The modified membranes maintained their performance for at least 30 days when stored at 4 °C. Finally, analysis of human serum samples confirmed that the PSA concentration as determined using the proposed platform was consistent with that determined with a conventional chemiluminescent immunoassay. Thus, this PSA analyzing platform is suitable for prostate cancer diagnosis in clinical settings.
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Affiliation(s)
- Ruohong Chen
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yipo Xiao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Hongtao Liu
- Instrumental Analysis and Research Center, Sun Yat-Sen University, Guangzhou 510275, China
| | - Ling Fang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.,Instrumental Analysis and Research Center, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jiahui Liu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xiaolin Ruan
- Department of Clinical Laboratory, Guangdong Women and Children Hospital, Guangzhou 511443, China
| | - Baowei Chen
- Southern Marine Science and Engineering Guangdong Laboratory, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
| | - Tiangang Luan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.,Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
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Sobsey CA, Ibrahim S, Richard VR, Gaspar V, Mitsa G, Lacasse V, Zahedi RP, Batist G, Borchers CH. Targeted and Untargeted Proteomics Approaches in Biomarker Development. Proteomics 2020; 20:e1900029. [DOI: 10.1002/pmic.201900029] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/10/2019] [Indexed: 01/24/2023]
Affiliation(s)
- Constance A. Sobsey
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - Sahar Ibrahim
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - Vincent R. Richard
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - Vanessa Gaspar
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - Georgia Mitsa
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - Vincent Lacasse
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - René P. Zahedi
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
| | - Gerald Batist
- Gerald Bronfman Department of OncologyJewish General HospitalMcGill University Montreal Quebec H4A 3T2 Canada
| | - Christoph H. Borchers
- Segal Cancer Proteomics CentreLady Davis InstituteJewish General HospitalMcGill University Montreal Quebec H3T 1E2 Canada
- Gerald Bronfman Department of OncologyJewish General HospitalMcGill University Montreal Quebec H4A 3T2 Canada
- Department of Data Intensive Science and EngineeringSkolkovo Institute of Science and TechnologySkolkovo Innovation Center Moscow 143026 Russia
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7
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Ferguson J, Patel D, Atkinson E, Rigsby P, Burns C. Continued provision of WHO International Standards for total and free PSA: Content and commutability of replacement preparations. Clin Biochem 2019; 71:58-66. [DOI: 10.1016/j.clinbiochem.2019.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 07/03/2019] [Accepted: 07/06/2019] [Indexed: 10/26/2022]
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8
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Clerico A, Belloni L, Carrozza C, Correale M, Dittadi R, Dotti C, Fortunato A, Vignati G, Zucchelli GC, Migliardi M. A Black Swan in clinical laboratory practice: the analytical error due to interferences in immunoassay methods. Clin Chem Lab Med 2018; 56:397-402. [PMID: 29220884 DOI: 10.1515/cclm-2017-0881] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/22/2017] [Indexed: 12/11/2022]
Abstract
It is well known that the results of immunoassay methods can be affected by specific or non-specific interferences, ranging from 0.4% to 4.0%. The presence of interference may greatly compromise the accuracy of immunoassay analyses causing an error in the measurement, producing false-positive or false-negative results. From a clinical point of view, these analytical errors may have serious implications for patient care because they can cause misdiagnosis or inappropriate treatment. Unfortunately, it is a very difficult task to identify the irregular analytical errors related to immunoassay methods because they are not detectable by normal laboratory quality control procedures, are reproducible within the test system, may be clinically plausible and are relatively rare. The first line of defense against erroneous results is to use in laboratory practice only immunoassay systems with the highest level of robustness against interference. The second line of defense is always taking into account the possibility of interference in immunoassay results. A correct approach should be addressed on identification of samples at high risk of interference. The attainment of this goal requires a critical review of the test result in relation to patient's clinical conditions and literature data, taking into account the analytical characteristics of the immunoassay system. The experts in immunoassay systems should make every effort to find some specific and reliable quality indicators for irregular analytical errors in order to better detect and monitor erroneous immunoassay results due to specific or non-specific interferences.
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Affiliation(s)
- Aldo Clerico
- Laboratory of Cardiovascular Endocrinology and Cell Biology, Department of Laboratory Medicine, Fondazione CNR Toscana G. Monasterio, Scuola Superiore Sant'Anna, Via Trieste 41, 56126 Pisa, Italy
| | - Lucia Belloni
- Dipartimento di Medicina di laboratorio, Arcispedale Santa Maria Nuova - IRCCS, Reggio Emilia, Italy
| | - Cinzia Carrozza
- Laboratorio Analisi 1, Fondazione Policlinico Universitario "A. Gemelli", Roma, Italy
| | - Mario Correale
- Clinical Pathology Unit, IRCCS De Bellis, Castellana Grotte, Bari, Italy
| | - Ruggero Dittadi
- Medicina di Laboratorio, Ospedale dell'Angelo ULSS 3 Serenissima, Mestre, Italy
| | - Claudio Dotti
- Dipartimento di Medicina di laboratorio, Arcispedale Santa Maria Nuova - IRCCS, Reggio Emilia, Italy
| | - Antonio Fortunato
- U.O.C. Patologia Clinica, ASUR Marche Area Vasta 5, Ascoli Piceno, Italy
| | | | | | - Marco Migliardi
- S.C. Laboratorio Analisi, A.O. Ordine Mauriziano di Torino, Torino, Italy
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Lang R, Leinenbach A, Karl J, Swiatek-de Lange M, Kobold U, Vogeser M. An endoglycosidase-assisted LC-MS/MS-based strategy for the analysis of site-specific core-fucosylation of low-concentrated glycoproteins in human serum using prostate-specific antigen (PSA) as example. Clin Chim Acta 2018; 480:1-8. [DOI: 10.1016/j.cca.2018.01.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/22/2018] [Accepted: 01/22/2018] [Indexed: 10/18/2022]
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10
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The clinical utility of mass spectrometry based protein assays. Clin Chim Acta 2016; 459:155-161. [DOI: 10.1016/j.cca.2016.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 05/25/2016] [Accepted: 05/30/2016] [Indexed: 11/22/2022]
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11
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Tormey WP. Prostate Cancer Risk Calculators Using ERSPC-derived Data Underestimate the Risk if the WHO IRP 96/670 Standard Is Used in Prostate-specific Antigen Analysis. Eur Urol 2015; 68:541-2. [DOI: 10.1016/j.eururo.2015.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 03/11/2015] [Indexed: 10/23/2022]
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Abstract
Glycans on proteins and lipids are known to alter with malignant transformation. The study of these may contribute to the discovery of biomarkers and treatment targets as well as understanding of cancer biology. We here describe the change of glycosylation specifically defining colorectal cancer with view on N-glycans, O-glycans, and glycosphingolipid glycans in colorectal cancer cells and tissues as well as patient sera. Glycan alterations observed in colon cancer include increased β1,6-branching and correlating higher abundance of (poly-)N-acetyllactosamine extensions of N-glycans as well as an increase in (truncated) high-mannose type glycans, while bisected structures decrease. Colorectal cancer-associated O-glycan changes are predominated by reduced expression of core 3 and 4 glycans, whereas higher levels of core 1 glycans, (sialyl) T-antigen, (sialyl) Tn-antigen, and a generally higher density of O-glycans are observed. Specific changes for glycosphingolipid glycans are lower abundances of disialylated structures as well as globo-type glycosphingolipid glycans with exception of Gb3. In general, alterations affecting all discussed glycan types are increased sialylation, fucosylation as well as (sialyl) Lewis-type antigens and type-2 chain glycans. As a consequence, interactions with glycan-binding proteins can be affected and the biological function and cellular consequences of the altered glycosylation with regard to tumorigenesis, metastasis, modulation of immunity, and resistance to antitumor therapy will be discussed. Finally, analytical approaches aiding in the field of glycomics will be reviewed with focus on binding assays and mass spectrometry.
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Affiliation(s)
- Stephanie Holst
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands; Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands; Division of BioAnalytical Chemistry, VU University, Amsterdam, The Netherlands
| | - Yoann Rombouts
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
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Klee EW, Bondar OP, Goodmanson MK, Trushin SA, Bergstralh EJ, Singh RJ, Anderson NL, Klee GG. Serum concentrations of prostate-specific antigen measured using immune extraction, trypsin digestion, and tandem mass spectrometry quantification of LSEPAELTDAVK peptide. Arch Pathol Lab Med 2014; 138:1381-6. [PMID: 25268201 DOI: 10.5858/arpa.2013-0462-oa] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Prostate-specific antigen (PSA) is a 34-kDa glycoprotein with chymotrypsin-like enzyme activity that circulates both in free forms and complexed to various enzyme inhibitors including antichymotrypsin and α2-macroglobulin. Prostate-specific antigen bound to α2-macroglobulin is not detected by commercial PSA immunoassays. OBJECTIVE To develop a mass spectrometry assay that detects the same forms of PSA as the immunoassays, which could serve as a reference for harmonizing PSA immunoassays. DESIGN Prostate-specific antigen was immune extracted from serum, trypsin was digested, and the LSEPAELTDAVK peptide was quantitated on an API 5000 spectrometer. Calibrators were made by adding 10% free and 90% antichymotrypsin-bound PSA to female sera. The assay was standardized to the World Health Organization 96/670 reference standard. Validation of clinical utility and comparisons with 2 immunoassays (Roche cobas and Beckman Access) were performed using frozen sera aliquots from 100 men undergoing prostate biopsy (50 negative, 50 with cancer) and 5 serial samples collected over time from 5 men with advanced prostate cancer. RESULTS The antibody extraction efficiency was greater than 99%. The assay has an analytic range from 1.2 to 76 ng/mL, with precision ranging from 8.6% at 1.5 ng/mL to 5.4% at 27 ng/mL. The mass spectrometry assay correlated well with 2 immunoassays. All 3 assays showed statistically equivalent separation of prostate cancer from benign disease using receiver operating characteristic curve analysis. CONCLUSIONS This mass spectrometry assay can reliably measure PSA concentrations in human serum and could serve as a reference standard for harmonizing PSA immunoassays.
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Affiliation(s)
- Eric W Klee
- From the Departments of Health Sciences Research (Dr E. Klee and Mr Bergstralh) and Laboratory Medicine and Pathology (Drs Bondar, Trushin, Singh, and G. Klee and Ms. Goodmanson), Mayo Clinic College of Medicine, Rochester, Minnesota; and the Plasma Proteome Institute, Washington, DC (Dr Anderson)
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14
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Goč S, Kosanović M, Golubović S, Hajduković L, Janković M. Determination of Prostate-Specific Antigen in Serum and a Reference Material by On-Chip Immunoaffinity Chromatography. ANAL LETT 2014. [DOI: 10.1080/00032719.2014.928884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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15
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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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