Abstract A011: Proteomic expression using exosomes in intraductal papillary mucinous neoplasms (IPMN) patients to inform risk stratification
Authors: Dhani Harmeet , Alexander Roberta V. , Hinestrosa Juan Pablo , Izaguirre-Carbonell Jesus , Keith Dove , Billings Paul R. , Cote' Gregory , Sears Rosalie 
Published: January 2024

Abstract
Introduction Intraductal papillary mucinous neoplasm (IPMN), the most common type of pancreatic mucinous cysts, harbor risks of malignant progression of approximately 50% and 5% when found in the main duct (MD) and branch duct (BD), respectively. Surgical resection is standard of care in patients with high-risk stigmata and in some “indeterminate” cases, while surveillance modalities, which may include invasive imaging, are recommended for cases of cysts with “worrisome features”. Given the poor prognosis of late-stage pancreatic cancer, it is critical to accurately risk-stratify patients with IPMNs. We conducted a pilot study to evaluate the association of IPMN features with protein markers using extracellular vesicles (EVs), including exosomes, isolated from the blood of patients with resected IPMNs. Experimental procedure We evaluated 19 patients with IPMNs who underwent surgical resection (Whipple or distal pancreatectomy). Blood was collected before surgery and the EVs were isolated from plasma using an alternating current electrokinetics (ACE) platform. The concentration of 52 EV proteins was measured using a multiplex immunoassay. Surgical explant pathology reports were available and reviewed on all 19 patients. Data are presented as average concentration and 95% CI, and p-values represent the two-tailed t-test. Results Average age was 69 years (range: 47-83) and, of the 19 patients, 12 (63%) were male. Seventeen patients never smoked or were former smokers (quit &gt; 20 years) before sample collection. A total of 14 patients had acute or chronic pancreatitis (7 historical; 7 found in surgical explant) while 4 patients had previously undiagnosed pancreatic intraepithelial neoplasia (PanIN) at the time of surgery. In our EV analysis, we found multiple EV protein biomarkers to be elevated in patients with various IPMN characteristics. Marker A was significantly elevated in patients with high-grade dysplasia (n=10) compared to low-grade dysplasia (n=9) (10.8 [8.4-13.2] vs. 7.5 [5.8 - 9.2] pg/mL, respectively, p = 0.0241), as defined by surgical explant pathology. When examining 13 patients with main-duct or mixed-type IPMNs, markers B, C, and D were elevated compared to the 6 patients with branch-duct or unspecified IPMNs (marker B: 1.9 [1.4-2.3] vs. 1.1 [0.9-1.4] ng/mL, p=0.0099; marker C: 524.3 [400.2-648.4] vs. 318.8 [209.9-427.7] pg/mL, p=0.0102; marker D: 65.8 [43.8-87.7] vs. 39.9 [31.7-48.1] pg/mL, p=0.0281). Conclusions In this pilot study that evaluated 19 patients with IPMNs, we identified multiple EV proteins that are differentially expressed in subgroups of patients. Our findings suggest that these differentially expressed proteomic markers can lead to the development of an algorithm for IPMN risk-stratification and possibly help discern histopathologic grade. Future studies will expand on these preliminary results with the aim of identifying a panel of biomarkers that can risk-stratify IPMNs to guide medical decision-making.
Citation Format: Harmeet Dhani, Roberta V. Alexander, Juan Pablo Hinestrosa, Jesus Izaguirre-Carbonell, Dove Keith, Paul R. Billings, Gregory Cote', Rosalie Sears. Proteomic expression using exosomes in intraductal papillary mucinous neoplasms (IPMN) patients to inform risk stratification [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A011.