 CTCF binds to an average of about 55,000 DNA sites in 19 diverse cell types (12 normal and 7 immortal) and in total 77,811 distinct binding sites across all 19 cell types.CTCF’s ability to bind to multiple sequences through the usage of various combinations of its zinc fingers earned it the status of a “multivalent protein”.More than 30,000 CTCF binding sites have been characterized.