Based on the existed information [13, 14], M2 macrophages communicate with the surrounding cells through secreting various molecules, such as EGF, PDGF, VEGF, and TGF-β1, which are all identified as pivotal contributors for cancer aggressiveness [15, 16], but it is still unclear whether M2 macrophages facilitate GBM progression through secreting those factors. Here, EGF is linked to cancer.