Systemic Communication via Extracellular Vesicles in Cancer: The Body’s Wireless Internet System

Functional integration in eukaryotic organisms is achieved, on one hand, through a hierarchical architecture and, on the other, through the communication between the cells, tissues, and organs via secreted factors, such as cytokines, chemokines, metabolites, hormones, as well as extracellular vesicles (EVs). Communication between cells, tissues, and organs is essential both in health, when it is crucial for homeostasis maintenance, and in disease, when it becomes corrupted during the development and progression of systemic diseases, particularly in cancer. Cancer is a systemic disease even before it becomes clinically apparent. The host organism is not a passive bystander during cancer development, but it actively contributes to the process from its inception. Once formed, the tumor exerts its systemic effects, effectively “hacking” into the various host communication systems to support cancer growth. Here, we highlight the multifaceted roles of EVs in the tumor-host communication. This communication is especially important for the metastatic process and in orchestrating therapeutically intractable complications associated with advanced cancers, such as cachexia. Ultimately, deciphering the complex interactions between the tumor and its host will lead to novel approaches to interrupt this pathologic communication and to develop more effective anticancer therapies.