Serum N-glycans outperform CA19-9 in diagnosis of extrahepatic cholangiocarcinoma.

Extensive efforts have been devoted to improve the diagnosis of extrahepatic cholangiocarcinoma (ECCA) due to its silent clinical character and lack of effective diagnostic biomarkers. Specific alterations inN-glycosylation of glycoproteins are considered a key component in cancer progression, which can serve as a distinct molecular signature for cancer detection. This study aims to find potential serum N-glycan markers for ECCA. In total, 255 serum samples from patients with ECCA (n = 106), benign bile tract disease (BBD, n = 60) and healthy controls (HC, n = 89) were recruited. Only 2 mu L of serum from individual patients was used in this assay where the N-glycome of serum glycoproteins was profiled by DNA sequencer-assisted fluorophore-assisted capillary electrophoresis (DSA-FACE) technology. Multi-parameter models were constructed by combining the N-glycans and carbohydrate antigen 19-9 (CA19-9) which is currently used clinically. Quantitative analyses showed that among 13 N-glycan structures, the bifucosylated triantennary N-glycan (peak10, NA3F2) presented the best diagnostic performance for distinguishing ECCAfrom BBD and HC. Two diagnostic models (Glycotest1 and Glycotest2) performed better than single N-glycan or CA19-9. Additionally, two N-glycan structures (peak9, NA3Fb; peak12, NA4Fb) were tightly related to lymph node metastasis in ECCA patients. In conclusion, sera of ECCA showed relatively specific N-glycome profiling patterns. Serum N-glycan markers and models are novel, valuable and noninvasive alternatives in ECCA diagnosis and progression monitoring.