Extracellular vesicles as dynamic biomarkers: Monitoring therapeutic responses and drug resistance in cancer.

Cancer remains a major health challenge, with traditional monitoring approaches that are often limited in sensitivity and invasiveness. Liquid biopsies, particularly those involving circulating extracellular vesicles (EVs), have emerged as a promising non-invasive approach that holds efficient diagnostic and prognostic value, predicting disease development and patient outcomes. Furthermore, EVs can monitor therapy responses and detect potential resistance development. In this review, we delineate the diverse cargo within EVs, including proteins, lipids, RNAs, and DNA, and their potential implications for cancer progression. The clinical utilization of EVs as prognostic and treatment-monitoring biomarkers for various types of cancer is addressed in depth, with a focus on their ability to identify molecular signatures associated with drug resistance. We also present a comprehensive collection of studies on EV-derived biomarkers for monitoring treatment responses across various cancer types, as well as investigations into EV-derived biomarkers associated with therapeutic resistance. While the promise of EV biomarkers in cancer therapy monitoring is acknowledged, we also discuss in detail the existing challenges and future directions in this research area. This review ultimately improves our understanding of liquid biopsies, specifically EV biomarkers, paving the way for more personalized and effective dynamic biomarkers.