Exosomes and lung cancer: Roles in pathophysiology, diagnosis and therapeutic applications

Lung cancer is a malignancy with a high morbidity and mortality rate, and affected patients have low survival and poor prognosis. The therapeutic approaches for the treatment of this cancer, including radiotherapy and chemotherapy, are not particularly effective partly due to late diagnosis. Therefore, the search for new diagnostic and prognostic tools is a critical issue. Novel biomarkers, such as exosomes, could be considered as potential diagnostic tools for malignancies, particularly lung cancer. Exosomes are nanovesicles, which are associated with different physiological and pathological conditions. It has been shown that these particles are released from many cells, such as cancer cells, immune cells and to some degree normal cells. Exosomes could alter the behavior of target cells through intercellular transfer of their cargo (e.g. DNA, mRNA, long non-coding RNAs, microRNAs and proteins). Thus, these vehicles may play pivotal roles in various physiological and pathological conditions. The current insights into lung cancer pathogenesis suggest that exosomes are key players in the pathogenesis of this cancer. Hence, these nanovesicles and their cargos could be used as new diagnostic, prognostic and therapeutic biomarkers in the treatment of lung cancer. Besides the diagnostic roles of exosomes, their use as drug delivery systems and as cancer vaccines is under investigation. The present review summarizes the current information on the diagnostic and pathogenic functions of exosomes in lung cancer.