mRNA and protein levels of Notch1, Notch4, Dll1, Dll4, Jagged1, HEY1, HEY2, and HES1 are increased in brain tumors and associated with upregulation of vascular endothelial growth factor (VEGF) and phospho-AKT, together with a reduction of the tumor suppressor phosphatase and tensin homolog (PTEN)[33,46]. Here, JAG1 is linked to brain neoplasm.