Open AccessAffinity-free enrichment and mass spectrometry analysis of the ovarian cancer biomarker CA125 (MUC16) from patient-derived ascites
Author(s) -
Naviya Schuster-Little,
Roberta Fritz-Klaus,
Mark R. Etzel,
Niharika Patankar,
Saahil Javeri,
Manish S. Patankar,
Rebecca J. Whelan
Publication year - 2021
Publication title -
analyst (london. 1877. online)/analyst
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.998
H-Index - 153
eISSN - 1364-5528
pISSN - 0003-2654
DOI - 10.1039/d0an01701a
Subject(s) - biomarker , ovarian cancer , immunoassay , ascites , mass spectrometry , serous fluid , proteomics , chemistry , tandem mass spectrometry , biomarker discovery , chromatography , computational biology , cancer , biology , medicine , antibody , biochemistry , immunology , gene
Developing a mass spectrometry-based assay for the ovarian cancer biomarker CA125 (MUC16) is a desirable goal, because it may enable detection of molecular regions that are not recognized by antibodies and are therefore analytically silent in the current immunoassay. Additionally, the ability to characterize the CA125 proteoforms expressed by individuals may offer clinical insight. Enrichment of CA125 from malignant ascites may provide a high-quality source of this important ovarian cancer biomarker, but a reliable strategy for such enrichment is currently lacking. Beginning with crude ascites isolated from three individual patients with high grade serous ovarian cancer, we enriched for MUC16 using filtration, ion exchange, and size exclusion chromatography and then performed bottom-up proteomics on the isolated proteins. This approach of enrichment and analysis reveals that the peptides detected via mass spectrometry map to the SEA domain and C-loop regions within the tandem repeat domains of CA125 and that peptide abundance correlates with clinical CA125 counts.