The Relationship between Exosomes and Cancer: Implications for Diagnostics and Therapeutics

Exosomes are very small extracellular vesicles secreted by cells to local and distant tissues. These mini signal transporters elicit acute and chronic effects on recipient cells. Studies regarding exosomes and their relationship to disease, as well as healthy functions, are eliciting extraordinary excitement as data pours in from groups around the world. Reporting of exosome biogenesis, selective loading of cargo, directed release, and resulting changes in adjacent and distal cells are providing information that is changing the way we view cancer progression and treatment. As a result, the properties of exosomes are being exploited for diagnostic, prognostic, and therapeutic applications. First, by referring to the signaling molecules carried by exosomes, they are being tested as indicators of the presence of transformed cells in early stages of cancer. Secondly, the cargo of exosomes secreted from tumors have been linked to prognostic factors and metastatic properties. Thirdly, exosome-based therapies are being developed which utilize the inherent properties of these mini-transporters to affect and interfere with cancer. Exosome creation, loading, and release plays an important role in cancer formation, progression and organotropic metastasis. The developed and developing therapies should be considered with understanding of their advantages and pitfalls, as well as the various roles exosomes play in normal and pathogenic processes. The combination of previously discovered attributes of exosomes with new discoveries occurring daily provide valuable and additive relevant factors to be considered as we embark on the continued discovery of exosomes and their relationship to cancer diagnostics and therapeutics.