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Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry

CA125 is the most widely used tumour marker in ovarian cancer with unsatisfactory sensitivity and specificity especially at early stage. It is quantified by antibody-based immunoassays; however different molecular weight isoforms have been described in the literature which have never been validated...

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Autores principales: Weiland, Florian, Fritz, Katarina, Oehler, Martin K., Hoffmann, Peter
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Molecular Diversity Preservation International (MDPI) 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3431838/
https://www.ncbi.nlm.nih.gov/pubmed/22949840
http://dx.doi.org/10.3390/ijms13089942
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author Weiland, Florian
Fritz, Katarina
Oehler, Martin K.
Hoffmann, Peter
author_facet Weiland, Florian
Fritz, Katarina
Oehler, Martin K.
Hoffmann, Peter
author_sort Weiland, Florian
collection PubMed
description CA125 is the most widely used tumour marker in ovarian cancer with unsatisfactory sensitivity and specificity especially at early stage. It is quantified by antibody-based immunoassays; however different molecular weight isoforms have been described in the literature which have never been validated by mass spectrometry, potentially affecting the diagnostic accuracy and clinical reliability of the test. In this study, CA125 was detected by Western blot and its identity confirmed by mass spectrometry. Two-dimensional (2D) gel electrophoresis in combination with mass spectrometry revealed that positive Western blot signals up to 500 kDa are most likely false-positive interactions of M11-like and OC125-like antibodies. Fibronectin, identified as one of these false-positive interaction partners, increased the reading for CA125 in a first generation ELISA significantly (p = 0.02). The existence of low-molecular weight isoforms of CA125 is therefore questionable and is most likely reflecting cross-reactivity of the antibodies with other proteins. This would explain the conflicting reports on the molecular structure of CA125 and also the inconsistency of CA125 levels by different ELISAs. Our results are also the first steps towards a mass spectrometric assay for CA125 quantification, which would improve sensitivity and reliability.
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spelling pubmed-34318382012-09-04 Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry Weiland, Florian Fritz, Katarina Oehler, Martin K. Hoffmann, Peter Int J Mol Sci Article CA125 is the most widely used tumour marker in ovarian cancer with unsatisfactory sensitivity and specificity especially at early stage. It is quantified by antibody-based immunoassays; however different molecular weight isoforms have been described in the literature which have never been validated by mass spectrometry, potentially affecting the diagnostic accuracy and clinical reliability of the test. In this study, CA125 was detected by Western blot and its identity confirmed by mass spectrometry. Two-dimensional (2D) gel electrophoresis in combination with mass spectrometry revealed that positive Western blot signals up to 500 kDa are most likely false-positive interactions of M11-like and OC125-like antibodies. Fibronectin, identified as one of these false-positive interaction partners, increased the reading for CA125 in a first generation ELISA significantly (p = 0.02). The existence of low-molecular weight isoforms of CA125 is therefore questionable and is most likely reflecting cross-reactivity of the antibodies with other proteins. This would explain the conflicting reports on the molecular structure of CA125 and also the inconsistency of CA125 levels by different ELISAs. Our results are also the first steps towards a mass spectrometric assay for CA125 quantification, which would improve sensitivity and reliability. Molecular Diversity Preservation International (MDPI) 2012-08-09 /pmc/articles/PMC3431838/ /pubmed/22949840 http://dx.doi.org/10.3390/ijms13089942 Text en © 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. http://creativecommons.org/licenses/by/3.0 This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).
spellingShingle Article
Weiland, Florian
Fritz, Katarina
Oehler, Martin K.
Hoffmann, Peter
Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry
title Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry
title_full Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry
title_fullStr Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry
title_full_unstemmed Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry
title_short Methods for Identification of CA125 from Ovarian Cancer Ascites by High Resolution Mass Spectrometry
title_sort methods for identification of ca125 from ovarian cancer ascites by high resolution mass spectrometry
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3431838/
https://www.ncbi.nlm.nih.gov/pubmed/22949840
http://dx.doi.org/10.3390/ijms13089942
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