Multifucosylated Alpha-1-acid Glycoprotein as a Novel Marker for Hepatocellular Carcinoma

High-sensitivity and -specificity diagnostic techniques to detect early-stage hepatocellular carcinoma (HCC) are in high demand. Screening with serum HCC markers, such as alpha-fetoprotein, is not practical because they possess poor sensitivity and specificity. As such, we focused on glycan alterations of glycoproteins found in patient sera in an attempt to discover novel HCC markers that are more specific and sensitive than current HCC markers. Sera from 42 HCC patients and 80 controls, composed of 27 chronic hepatitis B patients, 26 chronic hepatitis C patients, and 27 healthy volunteers, were analyzed in this study. Glycopeptides obtained from serum proteins by trypsin digestion were enriched by ultrafiltration and Aleuria aurantia lectin-based affinity chromatography, followed by analysis using liquid chromatography time-of-flight mass spectrometry. The data were analyzed by our newly developed software, which calculates peak intensities and positions (m/z and elution time), aligns all sample peaks, and integrates all data into a single table. HCC markers were extracted from more than 30 000 detected glycopeptide peaks by t test, mean-fold change, and ROC analyses. As a result, we revealed that alpha-1-acid glycoprotein with multifucosylated tetraantennary N-glycans was significantly elevated in HCC patients, whereas the single fucosylated derivative was not.