Exosomes as potential sources of biomarkers in colorectal cancer.

Colorectal cancer (CRC), a common malignancy, is among the leading causes of cancer-related deaths worldwide. Developing novel biomarkers is an important public health strategy to effectively reduce the mortality of this disease. Recent studies have found that exosomes may be important sources of biomarkers in CRC. Exosomes are nanometer-sized membrane vesicles (30-200 nm) secreted by normal or cancer cells, which participate in intercellular communication by transporting RNAs and proteins. Accumulating evidence has shown that some differentially expressed RNAs and proteins in exosomes play key roles in the initiation and development of CRC and are potential candidates for malignancy detection. Accordingly, exploring the correlation between these exosomes and CRC may be beneficial for the development of novel biomarkers in this disease. Here, we summarize the important roles of exosomes as biomarkers in CRC diagnosis, as well as the application in the metastasis, chemoresistance, and recrudescence of CRC. In particular, we discuss the prospects and limitations of exosomes as tumor markers.