CTCF and cancer: The discovery that CTCF and BORIS have opposite effects on transcription of BAG1, some CT-genes, and on the epigenetic status of the IGF2/H19 ICR, has lead to the (albeit controversial [47]) hypothesis that CTCF and BORIS are antagonistic regulators of the common loci to which they bind, and that inappropriate interactions between them is cancer promoting [16],[52].