Updated project metadata. Exosomes are a subset of extracellular vesicles shuttling proteins, RNA, DNA and lipids crucial for cell–to–cell communication. Recent findings highlighted that exosomes, by virtue of their cargo, may also contribute to breast tumor growth and dissemination of metastasis. Indeed, these vesicles are gaining great interest as non-invasive cancer biomarkers. However, little is known on exosome biological and physical properties from breast malignant lesions and even less by non–malignant lesions such as breast fibroadenoma. The latter, being a non-malignant lesion, is clinically managed by conservative approaches. However, the molecular features of fibroadenoma are still largely unknown. In this pilot study, we attempt to purify and explore the proteomic profiling of breast benign and tumor exosomes from breast fibroadenoma, HER2+ and triple negative patient tumors as well from continuous cell lines by combining experimental and semi-quantitative approaches (BT-549, MCF10-A and MDA-MB-231). Interestingly, proteome-wide analyses showed 49 common proteins across breast fibroadenoma, HER2+, triple-negative malignant lesions and model cell exosomes. This is the first feasibility study evaluating physicochemical composition and proteome of extracellular vesicles from breast benign, malignant primary cells and immortalized cells. Our preliminary results may hold promises for freshly isolated primary cells protein identification with possible implications in breast cancer precision medicine.