Breast cancer remains a leading cause of cancer-related mortality worldwide, with obesity markedly increasing the risk in affected individuals. Liquid biopsy-based extracellular vesicles (EVs) offer a minimally invasive platform for molecular profiling of tumor-derived markers. Plasma small-EVs from obese, chemotherapy-naïve breast cancer patients (n = 76; stages I-III) and age-matched obese controls (n = 36) were enriched and characterized by high-resolution transmission electron microscopy, dynamic light scattering (DLS) and specific EV markers. Proteomic profile of the enriched small-EVs using nanoLC-MS/MS identified Fibronectin 1 (FN1) and von Willebrand Factor (VWF) as candidate markers. Bioinformatics and STRING networks revealed interactions with Syndecan-2 (SDC2) and Galectin-3 (Gal-3). As an independent validation, western blot confirmed that FN1, VWF, and SDC2 were higher enriched in the small-EVs of breast cancer with different stages than in those of normal and that high content of small-EVs FN1 and SDC2 was primarily associated with the aggressive triple-negative breast cancer (TNBC) subtype. Interestingly, Gal-3 was reduced in small-EVs but elevated in breast carcinoma tissues and microvesicle (MV)-enriched EVs. Functionally, treatment with TNBC-derived plasma small-EVs not only downregulated expression of epithelial marker CDH1, and upregulated expression of the mesenchymal markers ZEB2 and FN1 in low-invasive MCF-7 breast cancer cells, but also elevated expression of inflammatory and matrix-remodeling mediators (Il-6, Tnf-α, and Mmp-9) in BNL CL.2 normal liver cells. ROC-Plotter and drug-gene interaction analyses indicated associations with therapy response, with approved compounds targeting FN1 and VWF. Overall, these findings reveal proteomic signatures of minimally invasive plasma small-EVs as promising markers associated with diagnosis, molecular subtyping, disease progression, and guiding therapeutic strategies in obese breast cancer patients.
Copyright: © 2026 WalyEldeen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.