IDH1 and central nervous system cancer: A well-studied case of insulator dysfunction in IDH-mt occurs after hypermethylation of CBS and the consequent disruption of TAD boundaries, enabling the interaction of a constitutive EE with the promoter region of the receptor tyrosine kinase platelet-derived growth factor receptor A (PDGFRA) gene (enhancer adoption), a well-described glioma oncogene [11].