CTCF is a zinc finger protein involved in a variety of cell functions. Mutations of CTCF including missense, nonsense and frameshift mutations occur throughout the gene and have been reported in approximately 5% of acute megakaryoblastic leukemia, 2% of transient abnormal myelopoiesis, less than 5% of AML, less than 5% of MDS and less than 5% cases of ALL.