Abstract P048: Development of the diagnostic method for pancreatic cancer using novel isolation technology of extracellular vesicles

Abstract

Abstract Background: Extracellular vesicles (EVs) are secreted by all cells into extracellular fluids and are found in most body fluids, including blood and urine. EVs contain many bioactive molecules, including proteins, RNA, DNA, and phospholipids. EVs have been reported to be associated with various diseases, including cancer metastasis and progression, suggesting that they play an important role in cell-to-cell communication. EVs are a promising modality for liquid biopsy and their clinical applications are desired, but methods for EVs isolation and quantification are still controversial. Traditionally used methods include ultracentrifugation (UC), polymer-based precipitation, and immunoprecipitation (IP) against surface marker antigens, but they are often inadequate in recovery efficiency and purity and are not standardized. In addition, it is very difficult to separate and recover EVs from body fluids that contain many contaminants. Therefore, we developed the original IP method (EViSTEPTM) in which a chelating agent-based reagent combined with in-house antibodies (CD9 and CD63) separate EVs with high purity and high recovery from body fluids such as serum and plasma for clinical applications. In this study, we evaluated whether EViSTEPTM in combination with expression levels of a newly identified long non-coding RNA (lncRNA), LOC100507412 (HEVEPA), could be used for stratification of pancreatic ductal adenocarcinoma (PDAC). Methods: EVs were isolated from serum of PDAC (22 cases), intraductal papillary mucinous neoplasm (IPMN) (23 cases), and healthy controls (HC) (21 cases) using EViSTEPTM, and HEVEPA expression analysis was performed by digital droplet PCR. Results: In the analysis of HC, IPMN, and PDAC samples, HEVEPA was significantly more highly expressed in PDAC compared to HC and IPMN. In ROC analysis between PDAC versus non-PDAC (IMPN and HC), the AUC of HEVEPA (0.80) was comparable to other tumor makers such as CEA (0.48) and CA19-9 (0.89). Furthermore, the AUC improved to 0.99 when HEVEPA was combined with CA19-9 but was not significantly different from that of CA19-9 alone. Conclusion: EViSTEPTM enables us to analyze HEVEPA in EVs, and the combination of HEVEPA and CA19-9 is expected to improve the diagnostic performance of PDAC. The combination of the EViSTEPTM method of EVs isolation and HEVEPA expression levels was suggested to be useful for the stratification of PDAC. Citation Format: Yuta Shimizu, Kenji Takahashi, Fumi Asai, Tatsutoshi Inuzuka. Development of the diagnostic method for pancreatic cancer using novel isolation technology of extracellular vesicles. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P048.