Abstract: Work described herein reveals 3D regulatory landscapes of hESCs representative of early human development. This work also demonstrates that cohesin-associated CTCF loops, and the cohesin-associate enhancer-promoter loops within them, dominate the organization of TADs. The CTCF-CTCF loops form a chromosomal scaffold of insulated neighborhoods that are largely preserved in vertebrates, and enhancer-promoter interactions occur within these neighborhoods. Genes are regulated in the context of conserved insulated neighborhood structures. Loss of neighborhood structures occurs frequently in cancer cells, and proto-oncogenes can be activated by genetic alterations that disrupt specific 3D chromosome structures.