ZEB1 and glioblastoma: ZEB1 is able to modulate the expression of genes which are considered mediators of tumor cell migration and invasion, like E-cadherin, a cell membrane calcium-dependent glycoprotein responsible for cell−cell adhesion [22,31], or the guanine nucleotide exchange factor Prex1, which has been shown to be important for the invasion of GBM cells in vivo [32].