The mutational analysis reported here, and previous work by our group and others, shows that inactivating mutations of histone modifiers are rare, although EP300 and CREBBP are targets of chromosomal translocations in human leukaemias and EP300 and CREBBP are an uncommon target of mutations in epithelial cancers [13-15,45-47]. Here, CREBBP is linked to leukemia.