Finally, considering that the catalytic product of ECE1c, the endothelin-1 peptide (ET1), plays a role in vascularization and exogenously supplied ET1 induces migration and MMP expression in U251 cells [13,41], we wished to determine if ET1 expression was induced and, if so, to determine the potential effect of this induction on vasculogenic mimicry (VM) in our GBM cell clones. Here, EDN1 is linked to glioblastoma.