Abstract 2001: Proteomic analysis of plasma exosomes identifies biomarkers for liver and lung metastasis of colorectal cancer patients

Abstract Metastasis is the leading cause of mortality in colorectal cancer (CRC), with liver and lung Metastasis being the most common sites of progression. Although early detection of metastasis is crucial for improving patient outcomes, non-invasive predictive strategies remain limited. Exosomes, a class of extracellular vesicles encapsulating cell-derived proteins, DNA, mRNA, and miRNA within a lipid bilayer, closely reflect the molecular characteristics of their originating cells and exhibit exceptional stability in biological samples. These unique features position exosomes as promising candidates for biomarker discovery. In this study, we utilized label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze plasma samples from 19 individuals: 5 healthy controls, 7 CRC patients with liver metastasis, and 7 CRC patients with lung metastasis. Blood samples were collected between March 2017 and April 2021, with only plasma from patients who developed metastasis repeatedly and exclusively in the liver or lung during the observation period included in the analysis. From 500 µL of plasma, we extracted an average of 149.9 µg of protein (173.8 µg from healthy controls, 145.9 µg from liver metastasis samples, and 136.8 µg from lung metastasis samples) and identified 851 proteins for further investigation. Our findings revealed that exosomes from CRC patients with metastasis contained elevated levels of proteins associated with angiogenesis, cell differentiation, and cell adhesion—such as ANGPTL6, COL1A1, LAMA2, and RENL—compared to healthy controls. Specifically, VCAN and ANGPTL6 were significantly upregulated in liver metastasis, while CFD and CRTAC1 were highly expressed in lung metastasis. These proteins are known to play critical roles in tumor progression and metastasis across various cancer types. Kaplan-Meier survival analysis based on the mRNA expression levels of these proteins indicated that CRC patients with higher expression exhibited worse overall survival (OS) and relapse-free survival (RFS) compared to those with lower expression levels. Future research will focus on the functional characterization of these identified proteins, the isolation of liver- and lung-specific exosomes, and the identification of small RNA biomarkers. This study represents a significant step toward the development of liquid biopsy-based approaches, particularly leveraging exosomes, for the early prediction of liver and lung metastasis in CRC patients. Citation Format: Boyeon Kim, Jwa Hoon Kim, Jiwon Lee, Soohyeon Lee. Proteomic analysis of plasma exosomes identifies biomarkers for liver and lung metastasis of colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2001.