Role of tumour-derived exosomes in metastasis.

Tumour-derived exosomes (TDEs) are actively produced and released by tumour cells and carry messages from tumour cells to normal or abnormal cells residing at close or distant sites. TDEs participate in every process of tumour metastasis. However, the occurrence and development of tumours depend on the specific functions acquired by tumour cells on the primary and metastatic foci. In this review, we discussed that TDEs regulate the initial mechanism of metastasis, the formation of a pre-metastatic niche, immunosuppression and angiogenesis. In addition, we investigated the signalling pathways and effective components of TDEs and discussed that inhibition of exosomes can inhibit tumour progression. Finally, we discussed the application and future development of TDEs. An understanding of several molecular players and processes involved in metastasis can lead to the development of effective, targeted approaches to prevent metastasis and treat cancer.