Exosome beads array for multiplexed phenotyping in cancer

Exosomes are small extracellular vesicles (EV) released from all cells that differ from others EV in their cellular origin, abundance and biogenesis. These different types of extracellular vesicles are recognized as potential markers of human diseases, including cancer and, in recent years, there has been an important advance in the molecular characterization of exosomes from different types of cancer. In particular, due to their presence and stability in most body fluids and the similarity of their content with tumor cells, exosomes have great potential as non-invasive biomarkers for liquid biopsy. Nevertheless, the use of exosomes for diagnostic purposes has been limited by the lack of reproducible methods. Flow cytometry is a technique well adapted for a reproducible analysis of clinical samples. However, conventional flow cytometers do not allow the detection of particles < 300 nm based on forward scattered light (FSC), and therefore do not allow the direct detection of exosomes. To overcome this limitation, the use of microsphere bead-based flow cytometry assays is proposed, which, together with an adequate selection of markers, would contribute to making liquid biopsy based on exosomes a reality. Significance: Exosome play a crucial role in cell-to-cell communication. Tumor exosomes are abundant in cancer patient's peripheral blood, also in the central nervous fluid systems which contribute to spread their function from proximal to distance tissues. Exosomes are an emerging field that could be exploited such as non-invasive biomarker and delivery vehicles in cancer therapy. There is an urgent need for technological advancements on exosome isolation, detection and characterization.