In multicellular organisms both health and disease are defined by patterns of communication between the constituent cells. In addition to networks of soluble mediators, cells are also programed to exchange complex messages pre-assembled as multimolecular cargo of membraneous structures known extracellular vesicles (EV). Several biogenetic pathways produce EVs with different properties, and known as exosomes, ectosomes, and apoptotic bodies. In
cancer, EVs carry molecular signatures and effectors of the disease, such as mutant
oncoproteins, oncogenic transcripts,
microRNA, and DNA sequences. Intercellular trafficking of such EVs (oncosomes) may contribute to horizontal cellular transformation, phenotypic reprograming, and functional re-education of recipient cells, both locally and systemically. The EV-mediated, reciprocal molecular exchange also includes
tumor suppressors,
phosphoproteins,
proteases,
growth factors, and bioactive
lipids, all of which participate in the functional integration of multiple cells and their collective involvement in
tumor angiogenesis,
inflammation, immunity, coagulopathy, mobilization of bone marrow-derived effectors,
metastasis, drug resistance, or cellular stemness. In cases where the EV role is rate limiting their production and uptake may represent and unexplored anticancer
therapy target. Moreover, oncosomes circulating in biofluids of
cancer patients offer an unprecedented, remote, and non-invasive access to crucial molecular information about
cancer cells, including their driver mutations, classifiers, molecular subtypes, therapeutic targets, and
biomarkers of drug resistance. New nanotechnologies are being developed to exploit this unique
biomarker platform. Indeed, embracing the notion that human
cancers are defined not only by processes occurring within
cancer cells, but also between them, and amidst the altered
tumor and systemic microenvironment may open new diagnostic and therapeutic opportunities.