EV-miR-21 from neuroblastoma cells is transferred to monocytes, which can differentiate into macrophages, and upregulates miR-155 expression by binding TLR8; the educated monocytes in turn secrete EV-miR-155 to induce chemotherapy resistance by targeting TERF1 in neuroblastoma cells [199]. The gene discussed is TLR8; the disease is neuroblastoma.