Glycosylation Profiling of Neoplastic Biomarker Alpha Fetoprotein Through Intact Mass Protein Analysis

Alpha fetoprotein (AFP) is a circulating cancer biomarker implicated in multiple neoplastic malignancies, including hepatocellular carcinoma (HCC). AFP glycoforms with core fucosylation structure (AFP-L3) are used clinically as a biomarker, to predict risk of developing HCC and to monitor its recurrence. Mature AFP has a single glycosylation site, while there is a high degree of structural variation in AFP-glycan modifications. Because AFP has single glycosylation site, masses of intact AFP proteoforms can be used to differentiate and identify PTM in their native states. We developed a method for intact AFP glycoform analysis that utilizes AFP-specific immune-enrichment, followed by LC-high resolution mass spectrometry (LC-HRMS) analysis to differentiate and quantitate the relative abundance of AFP glycoforms and evaluated the method’s performance.