In fact, in serum stimulation of NIH-3T3 fibroblasts [190] and platelet-derived growth factor (PDGF) stimulation of T98G-glioblastoma [181] the CArG box has proven to be functional but in hippocampal neuronal cultures [191], [192], cerebellar cortex [127] and in vivo [193] conditions general findings are in favor of a CREB and MEF2 determinant role. This evidence concerns the gene CREB1 and glioblastoma.