rBC2LCN-reactive SERPINA3 is a glycobiomarker candidate for pancreatic ductal adenocarcinoma

Early detection is urgently needed to improve the patient's pancreatic ductal adenocarcinoma (PDAC) survival. Previously, we identified a novel tumor-associated glycan, H-type3, which is expressed on PDAC cells and is detected by rBC2LCN (recombinant N-terminal domain of BC2L-C identified from Burkholderia cenocepacia) lectin. Here, we identified that SERPINA3 is an rBC2LCN-reactive glycoprotein (BC2-S3) secreted from PDAC cells into the blood in patients with PDAC by liquid chromatography-tandem mass spectrometry analysis and lectin blotting. In immune staining, BC2-S3 was detected specifically in the tumor but not in normal tissues of PDAC. Lectin-ELISA was then developed to measure the serum level of BC2-S3 in healthy control (HC, n = 99) and patients with PDAC (n = 88). BC2-S3 exhibited higher in patients with PDAC than in those with HC. BC2-S3 showed similar diagnostic performance in all stages of PDAC (stages IA-IV, true positive rate = 76.1%, true negative rate = 81.8%) to CA19-9 (72.7%, 75.8%). Remarkably, BC2-S3 showed a significantly higher detection rate (89.7%) for early stage PDAC (IA-IIA) than CA19-9 (62.1%, P = 0.029). The combination of BC2-S3 and CA19-9 further improved the diagnostic ability for all stages of PDAC (81.8%, 87.9%). In conclusion, BC2-S3 is a glycobiomarker candidate for PDAC.