The role of exosomes in liquid biopsy for cancer diagnosis and prognosis prediction

Abstract

Liquid biopsy is a revolutionary strategy in cancer diagnosis and prognosis prediction, which is used to analyze cancer cells or cancer-derived products through biofluids such as blood, urine and so on. Exosomes play a crucial role in mediating cell communication. A growing number of studies have reported that exosomes are involved in tumorigenesis, tumor growth, metastasis and drug resistance by delivering cargos including nucleic acids and protein. Thus, exosomes, as a new type of liquid biopsy, have the potential to be diagnostic or prognostic biomarkers. Herein, we elaborate on the current methods and introduce novel techniques for exosome isolation and characterization. Moreover, we elucidate the advantages of exosomes compared to other biological components in liquid biopsy and summarize the different exosomal biomarkers in cancer diagnosis and prognosis prediction.

Keywords: diagnosis; exosomes; liquid biopsy; prognosis.

FIGURE 1

The commonly used methods for exosomes isolation and characterization. Liquid biopsy mainly includes circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), exosomes and tumor‐educated platelets (TEPs). Currently, the commonly used methods for exosomes isolation consist of ultracentrifugation, density gradient centrifugation, filtration, size‐exclusion chromatography (SEC) and immunoaffinity‐based methods like ELISA. As for exosomes characterization, qRT‐PCR, next‐generation sequencing (NGS) and microarrays are employed in exosomal RNA while ELISA, western blot and proteomics are applied to exosomal protein [Color figure can be viewed at wileyonlinelibrary.com]