Exosomes biology: Function and clinical implications in lung cancer

Lung cancer is the most common malignancy in the United States, totaling 225,000 cases per year. In recent years, several new treatment options have become available based on the molecular and cellular characterization of the disease. More recently, "liquid biopsies" have received attention to complement traditional tissue biopsies and to enhance the spectrum of analysis for tumor-derived factors. As one of these tumor characteristics, extracellular vesicles (EVs) are lipid bilayered EVs that can cargo a variety of factors, including growth factors and their receptors, RNA transcripts, microRNAs, and DNA, among others. Initial acceptance as mere physiological products has been attributed to the presence of exosomes in healthy individuals, and the large diversity of exosomes that have made the assignment of distinct pathophysiological roles difficult. While their role in clinical application has not yet been established, they have emerged from their once thought innocent role as a bystander to a critical mediator of intratumoral signaling, tumor progression, chemotherapy resistance, and metastasis. In this review, we have summarized the structure and biology of EVs, their role in lung cancer, and the potential diagnostic and therapeutic implications for the treatment of this complex disease.