In prostate (PCa) and colorectal (CRC) cancer, there is a need to improve patient stratification techniques that aid diagnostic and prognostic decision-making. To fulfill this unmet clinical need,... Show moreIn prostate (PCa) and colorectal (CRC) cancer, there is a need to improve patient stratification techniques that aid diagnostic and prognostic decision-making. To fulfill this unmet clinical need, the measurement of disease-related biological parameters known as “biomarkers” from biofluids is an approach with the potential to develop noninvasive tests as well as achieve greater clinical accuracy and personalized medicine. Thus, this thesis focused on developing a better understanding of biomarkers relevant to PCa and CRC as well as advancing analytical methodology and achieving methodological advancements for the purpose of biomarker discovery. In chapters two and three, a large diversity of prostate-specific antigen (PSA) cleaved and non-cleaved proteoforms (PCa) with different N-glycosylation patterns were determined in urine and seminal fluid using capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS), some of which are relevant for PCa patient stratification. In addition, the data processing workflow was improved in chapter three in order to enable larger studies of intact proteoforms to be performed. Furthermore, chapter four developed a reversed phase-liquid chromatography (RPLC)-MS method whereby it was possible to determine sialic acid linkages and positional isomers in released N-glycans following fluorescent labeling and sialic acid derivatization. This method was applied in chapter five to study serum N-glycosylation profiles in CRC and it was demonstrated that specific N-glycan isomers are implicated in the disease and differences between histological types were eradicated following surgery. Show less
