Hydrophilic interaction liquid chromatography contributes to integrated N-glycoproteomics analysis of human saliva for lung cancer

We aimed to in-depth characterize and quantify salivary N-glycoproteomics. HILIC enrichment and LC-MS/MS were combined to investigate salivary glycosylation both at deglycopeptides level and glycopepeptides level, and alterations in site-specific glycoforms for human saliva were detected between lung cancer patients and healthy subjects. Firstly, intact glycopeptides were enriched from human saliva through using HILIC. Obtained intact glycopeptides were characterized by LC-MS/MS directly. Furthermore, the glycosylation sites were fully identified by LC-MS/MS followed by incubating with PNGase F. The developed workflow was applied to compare N-glycosites and intact N-glycopeptides in lung cancer group and healthy control group. Dysregulated N-glycosites as well as site-specific glycoforms were confidently observed in lung cancer and their potential value in clinical applications will be discussed.