Discovery of Core-Fucosylated Glycopeptides as Diagnostic Biomarkers for Early HCC in Patients with NASH Cirrhosis Using LC-HCD-PRM-MS/MS

Aberrant changes in site-specific core fucosylation (CF) of serum proteins contribute to cancer development and progression, which enables them as potential diagnostic markers of tumors. An optimized data-dependent acquisition (DDA) workflow involving isobaric tags for relative and absolute quantitation-labeling and enrichment of CF peptides by lens culinaris lectin was applied to identify CF of serum proteins in a test set of patients with nonalcoholic steatohepatitis (NASH)-related cirrhosis (N = 16) and hepatocellular carcinoma (HCC, N = 17), respectively. A total of 624 CF peptides from 343 proteins, with 683 CF sites, were identified in our DDA-mass spectrometry (MS) analysis. Subsequently, 19 candidate CF peptide markers were evaluated by a target parallel reaction-monitoring-MS workflow in a validation set of 58 patients, including NASH-related cirrhosis (N = 29), early-stage HCC (N = 21), and late-stage HCC (N = 8). Significant changes (p < 0.01) were observed in four CF peptides between cirrhosis and HCC, where peptide LGSFEGLVn¹⁶⁰LTFIHLQHNR from LUM in combination with AFP showed the best diagnostic performance in discriminating HCC from cirrhosis, with an area under curve (AUC) of 0.855 compared to AFP only (AUC = 0.717). This peptide in combination with AFP also significantly improved diagnostic performance in distinguishing early HCC from cirrhosis, with an AUC of 0.839 compared to AFP only (AUC = 0.689). Validation of this novel promising biomarker panel in larger cohorts should be performed.