Determination of Hepatocellular Carcinoma Serum Polypeptide Based on Antibody Pre-concentration Coupled with Mass Spectrometry

Polypeptide antibody pre-concentration method coupled with mass spectrometry have been established for determination of serum polypeptide. Polypeptide was captured by agarose beads followed by binding of specific polyclonal antibodies from serum. After timed washing steps, the remaining bound polypeptides were eluted from the beads and detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The ion signals of protein A agarose bead-based platform amenable to high throughput peptide capture followed by mass spectrometry were achieved with enough precision (RSD < 12%) and accuracy (about 10% relative error) for quantifying biomarkers in the physiologically relevant nM range. The method to detect pep5 in the clinical hepatocellular carcinoma serum had the sensitivity of 78.0% and specificity of 90%. The method is appropriate for the detection of low concentration biomarkers in clinical samples, and it will be significant for earlier diagnosis of cancers.