Recent work has highlighted that these cells actively promote glioma invasion through a variety of mechanisms, including activation of matrix metalloproteases (MMPs) [85] and secretion of transforming growth factor-β [86,87] and EGF secretion [88] and through synergistic GBM-derived colony-stimulating factor-1 (CSF-1). The gene discussed is CSF1; the disease is glioblastoma.