EGF and central nervous system cancer: A number of TAM-secreted factors, including stress-inducible protein 1 (STI1) [43], epidermal growth factor (EGF) [25], TGF-β [44,45], and matrix metallopeptidase-2 (MMP-2) [46], have been shown to enhance proliferation and invasiveness of glioma cells (Figure 1).