Abstract C004: Liquid biopsy based on the lipid profiles in plasma-derived extracellular vesicles which can be utilized for breast cancer diagnosis

Abstract

Abstract Lipids are a major component of cells that can influence multiple cellular functions. Our group previously found that the breast cancer cells could dramatically change their lipid profile during their progression. Thus, we hypothesized that the lipid profile of extracellular vesicles (EVs) could be used as a biomarker for breast cancer (BC) since the lipid profiles of breast cancer cells can be reflected in that of EVs secreted from cancer cells. In the present study, we optimized a method to isolate EVs from human plasma samples that could be used for the comprehensive lipid analysis. We then explored specific lipid profiles in plasma-derived EVs that could discriminate BC and healthy individuals, tumor subtypes and stages. Plasma-derived EVs from breast cancer (n = 105), benign (n = 11), and healthy individuals (n = 43) were used for lipid analysis. The results showed that the change in proportion of the lipids in the EVs could well discriminate stages and subtypes of BC. The proportion of major phospholipids, phosphatidylethanolamines, phosphatidylserines, phosphatidylcholines (PCs) and phosphatidylinositols (PIs) showed different patterns at different stages. Importantly, PI (18:0/20:3), which we previously identified as a lipid biomarker of disease progression expressed in the primary breast cancer tissue, showed a similar trend in the plasma-derived EVs. This finding supports our initial hypothesis. Besides the phospholipids, sphingomyelins were found to be higher in stage IV. With regard to tumor subtypes, PCs and ceramides were enriched in HER2-positive subtype, while lysoPCs and polyunsaturated triglycerides were enriched in triple negative subtype. Furthermore, a BC diagnostic model consisting of three lipids was successfully established and the model showed good performance in discriminating between healthy individuals and BC in the two independent data sets (the area under the ROC curve was estimated around 0.759 to 0.804). In conclusion, profiling of lipids in plasma-derived EVs has the potential to be used as a liquid biopsy that can diagnose BC, and its stages and subtypes. Further validation and improvement in EV isolation technique would be needed to achieve sufficient performance sufficient for clinical application. Citation Format: Masahiro Kawashima. Liquid biopsy based on the lipid profiles in plasma-derived extracellular vesicles which can be utilized for breast cancer diagnosis [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C004.