Multiple lectin assays in detecting glycol-alteration status of serum NRG1 in papillary thyroid cancer.

Background: Neuregulin 1 (NRG1) is a membrane glycoprotein mediating cell-to-cell signaling and has a crucial role in the growth and development of various organ systems. Our study explored its diagnostic value in distinguishing BRAF V600E mutant status in papillary thyroid cancer (PTC) patients by analyzing multiple glycan patterns of serum NRG1 through lectin assays.

Methods: We first extracted serum from PTC patients and tested BRAF V600E mutation by immunohistochemical (IHC) staining. Then we applied antibody overlay lectin microarray and lectin blot to detect glycol-alterations of NRG1. Then Aleuria aurantia lectin (AAL) ELISA was performed according to ELISA index to test the protein fucosylation level of NRG1 (Fuc-NRG1).

Results: We got glycan profiles of 14 lectins, including GNL, GSL2, AAL, BPL, ECL, CAL, NML, HHL, PHA-L, RCA-I, ConA, DBA, PWA and LEL. Six of them, namely, GSL2, BPL, NML, HHL, PHA-L and LEL, had significantly increased binding affinity capacity in BRAF(+) PTC compared with BRAF(-) PTC controls. LEL, BPL and NML tended to bind to NRG1 in BRAF(+) PTC group. Both AAL ELISA and protein ELISA assays showed that the fucosylated structures of NRG1 had a remarkable increase in BRAF V600E mutant PTC patients compared with BRAF wild type PTC controls.

Conclusions: This study sheds a new light on the role of NRG1 glycosylation in PTC. NRG1 could serve as a supplementary glycobiomarker for BRAF indicator in discrimination of PTC patients with BRAF wild type negative fine needle aspiration results.