Further confirming a prominent Wnt signaling activation in GBM cells, through large-scale whole genome approaches it has been demonstrated that they exhibit epigenetic-dependent decreased expression of several Wnt pathway inhibitors, such as Wnt Inhibitory Factor 1 (WIF1), Dickkopf inhibitors (DKKs), and Secreted Frizzled Related Protein 1 (SFRP1) [29,101,106,107,108]. This evidence concerns the gene SFRP1 and glioblastoma.