From discovery to clinical implementation of a pancreatic blood biomarker, apolipoprotein A2 isoform.

Pancreatic cancer is a rare and refractory cancer, and the development of blood biomarkers for the enrichment of high-risk individuals who have risk factors for pancreatic cancer from the asymptomatic population is an unmet medical need. We identified abnormalities in the C-terminal truncation of the apolipoprotein A2 dimer (apoA2-isoforms: apoA2-i) in the blood of pancreatic cancer patients through proteomic analysis, and we have reported the potential for diagnosing resectable pancreatic cancer by detecting these abnormalities. We successfully developed enzyme-linked immunosorbent assay (ELISA) reagents for measuring apoA2-i for research use only, and then the basic data for diagnosing pancreatic cancer were accumulated by several studies using these reagents. In 2023, ELISA for measuring apoA2-i was regenerated by the regulation under the Japanese Quality Management System (QMS), it received marketing approval in Japan as an diagnostic (IVD) kit to aid in the diagnosis of pancreatic cancer, and it is now used in clinical practice. This review chronicles the journey from the initial discovery through omics research, to demonstrating clinical utility via multicenter studies in Japan and international collaborative research using the research reagent and validating the clinical performance of the IVD ELISA kit through a regulatory, science-guided, clinical trial in Japan, and finally to recent activities in the USA.