Exosomes are endosome-derived vesicles secreted by many cell types, including tumor cells. The vesicles are
formed intracellularly by invagination followed by fusion with the multivesicular body (MVB). The MVB ultimately
merges with the plasma membrane, leading to exocytosis of the exosomes, which consequently have a similar
membrane protein composition as their cell of origin; this provides the exosomes with unique biosignatures.
Furthermore, these circulating exosomes participate in cellular communication by transporting mRNAs,
microRNAs, and proteins to target cells where they can elicit biological responses. This study compared the
biosignatures identified from prostate cancer (PCa) cell line-derived exosomes to those found in exosomes
isolated from the plasma of PCa patient samples.