Exosomes in Tumour Immunity

Exosomes secreted by cancer cells are dynamic and highly complex, and the field as it stands remains somewhat controversial. It may be that, in early neoplastic lesions, cancer cells and the exosomes they produce have not yet acquired the potent suppressive molecules and mechanisms described here. Under such conditions, exosomes may play an important role in disseminating relevant tumour rejection antigens to the immune system, assisting the immune response, through the activities of dcs. However, by its very existence, progressive disease has overcome or overwhelmed the immune response, and exosomes in these scenarios harbour multiple mechanisms for attenuating several branches of immunity. Identifying the factor or factors responsible for this possible switch from immunogenic to immune-suppressive exosomes will be a major challenge, but will in turn offer exciting novel therapeutic opportunities for blocking tumour immune escape while retaining efficient tumour-antigen handling by the immune system.