Exosomes as emerging biomarkers in breast, lung, and colorectal cancer diagnosis: A comprehensive review.

Although exosome research has advanced considerably, clinical implementation remains limited. In contrast to previous reviews that catalog numerous biomarkers, this review focuses on translationally ready candidates for breast, lung, and colorectal cancers. Exosomal signatures address key diagnostic challenges, such as enabling tissue-free molecular subtyping in breast cancer, distinguishing malignant from benign nodules in lung cancer, and detecting CEA-negative or premalignant adenomas in colorectal cancer. This review critically assesses clinically advanced biomarkers-including miRNAs, lncRNAs, circRNAs, and proteins-and highlights those with validated, high diagnostic performance relative to current standards (e.g., CEA, imaging). Single biomarkers often fail to capture tumor heterogeneity, whereas multi-omic panels integrated with clinical data improve diagnostic accuracy. Exosomal biomarkers should, therefore, be considered adjuncts to standard diagnostics, functioning as triage tools to enhance patient management. The integration of exosomes into clinical workflows holds significant promise for non-invasive, early cancer detection, and personalized medicine.