HEY1 and brain neoplasm: Notch1, Notch4, DLL1, DLL2, JAG1, Centromere-binding protein-1 (CBF1), Hairy/enhancer-of-split related with YRPW motif protein-1 (HEY1), HEY2, and hairy and enhancer of split-1 (HES1) mRNA and protein levels are higher in brain tumor cells than in normal brain tissue, and also with increased VEGF and Phosphorylated protein kinase, strain AK, Thymoma (pAKT) expressions, and decreased Phosphatase and tensin homolog (PTEN) levels [15,16,17].