Larger Size Extracellular Vesicle As Early Biomarker In Patients With Metastatic Pancreatic Cancer.

234Background: Current research suggests that tumor-derived extracellular vesicles (EVs) play an important role in tumor progression especially with regard to metastasis. Atypically large EVs have been reported to have the ability to transport bioactive molecules through the blood stream. Therefore, EV physical properties such as diameters and concentrations may have a biological impact on tumor progression. However, it has not been described which characteristics are clinically relevant in the longitudinal assessment of tumor progression and chemo-response. Methods: Plasma from 19 metastatic PDAC patients was collected at treatment-naive baseline and in more than 2 consecutive assessments during chemotherapy between May 2015 and July 2016. EVs from plasma were isolated using a sequential centrifugation protocol, confirmed as described previously and analyzed using the Particle Metrix (Zetaview, Diessen, Germany) and proprietary software. The clinical variables along with concentration and size distributi...