Abstract 1038: Identification of diagnostic biomarkers for colon adenocarcinoma by analyzing proteins in human-derived extracellular vesicles and particles

Abstract

Abstract There is an unmet medical need for circulating biomarkers to improve early cancer detection in colon adenocarcinoma (COAD). We investigated the proteomic profile of extracellular vesicles and particles (EVPs) from the colon tissue explants and plasmas in COAD. The research aims to overcome the limitations of traditional serum Carcinoembryonic Antigen (CEA) testing and invasive procedures like colonoscopy. We analyzed EVPs sourced from tumor and adjacent non-tumor tissues and preoperative and postoperative plasma in COAD patients to identify potential EVP-based tumor diagnostic markers. In the Discovery phase with 50 COAD patients, we conducted a proteomic analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), identifying approximately 50 markers each from tissue explants and plasma. These markers were validated in an independent cohort of 104 participants, including 84 COAD patients and 20 healthy controls. We utilized ELISA to quantify 11 selected EVP proteins. Notably, seven of these proteins exhibited significant differential expression in preoperative and postoperative plasma, highlighting their diagnostic relevance. These seven proteins also showed marked elevation in preoperative plasma compared to healthy controls, reinforcing their potential as diagnostic markers. The study extended to evaluate the diagnostic accuracy of these seven proteins, referred to as "EV-7 levels", across various stages of COAD. Their performance was compared with serum CEA levels and plasma cfDNA mutation rates, as detected by an FDA-approved liquid biopsy assay. The EV-7 levels demonstrated superior detection rates in the early stages of COAD, particularly in Stages I and II, in contrast to the serum CEA method. Among the 84 patients, 73 (86.9%) exhibited EV-7 levels exceeding the established cut-off. In the validation cohort, EV-7 levels were more accurate across different COAD stages than serum CEA levels and cfDNA mutation rates. CEA levels above 5 ng/ml were 27%, 45%, 42%, and 64% for Stages I through IV. cfDNA somatic mutation rates were 60%, 80%, 75%, and 75%. EV-7 levels exceeding the cut-off were 73%, 100%, 88%, and 84%, respectively, with Stages I and II having the highest detection rate among the three methods. ROC curve analysis for EV-7 levels in Stages I to IV showed statistically significant, with AUC values of 0.913, 1.000, 0.985, and 0.984, respectively. Our findings indicate that the seven EVP proteins are significantly present in the plasma of early-stage COAD patients. Integrating these markers with current diagnostic approaches could improve early cancer detection, showing promise for practical application in clinical settings. Citation Format: Yura Seo, Yoon Dae Han, Linda Bojmar, Kyung-A Kim, Yurin Seo, David Lyden, Han Sang Kim. Identification of diagnostic biomarkers for colon adenocarcinoma by analyzing proteins in human-derived extracellular vesicles and particles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1038.