BC cells transmit sEV-miR-106b-5p and sEV-miR-18a-5p to macrophages and induce PD-L1 expression through the PTEN/AKT and PIAS3/STAT3 signaling pathways, which also leads to macrophage polarization and the development of BC lung metastasis [219]. The gene discussed is STAT3; the disease is breast cancer.