The 3D Language of Cancer: Communication via Extracellular Vesicles from Tumor Spheroids and Organoids.

Extracellular vesicles (EVs) have emerged as key mediators of intercellular communication, gaining recognition as tumor biomarkers and promising therapeutic targets. As the study of EVs advances, it has become increasingly clear that the cellular context in which they are produced significantly influences their composition and function. Traditional two-dimensional in vitro models are being progressively replaced by more advanced three-dimensional systems, such as tumor spheroids and organoids. These 3D models are particularly valuable in cancer research, providing a more accurate representation of the complex cellular and molecular heterogeneity that characterizes tumors, better mimicking the in vivo microenvironment compared to standard monolayer cultures. This review explores the role of EVs derived from tumor spheroids and organoids in key oncogenic processes, including tumor growth, metastasis, and interactions within the tumor microenvironment. We highlight how EVs contribute to the spread of cancer cells, affecting surrounding tissues, and promote immune evasion, which poses significant challenges in cancer therapy.