We focused on bFGF, epidermal growth factor (EGF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF) in further experiments, since bFGF and EGF play an important role in GBM CSC maintenance, [26, 27] HGF was shown to revert differentiated colorectal cancer cells to a CSC phenotype, [5] and VEGF was described to promote viability of GBM CSCs [28]. Here, HGF is linked to glioblastoma.