Figure 2.

Stroma‐to‐tumour communication via EVs. Resident cells at metastatic sites can, in turn, secrete EVs for uptake by tumour cells and promote secondary tumour outgrowth. In this instance, astrocyte‐derived EVs containing microRNA‐19a can be internalized by metastatic tumour cells in brain, cause their downregulation of PTEN and promote the secretion of chemokine CCL2. CCL2 further recruits IBAB⁺ myeloid cells to facilitate the metastatic tumour outgrowth