Additionally, tumor-modified astrocytes promote an immunosuppressive pro-tumoral environment through the release of EVs that induce, in cancer cells, the loss of the tumor suppressor PTEN (Phosphatase and Tensin Homolog); this event causes an increased secretion of the chemokine CCL2, which recruits IBA1+ myeloid cells that strengthen brain metastatic tumor cell growth [13]. The gene discussed is CCL2; the disease is neoplasm.