AML1 (also known as Runx1, CBFA2, and PEBP2alphaB) is a member of the core binding factor (CBF) family of transcription factors. It is required for normal development of all hematopoietic lineages. AML1 forms a heterodimeric DNA binding complex with its partner protein CBFbeta and regulates the expression of cellular genes by binding to promoter and enhancer elements. AML1 is commonly translocated in hematopoietic cancers: chromosomal translocations include t(8;21) AML1-ETO, t(12;21) TEL-AML, and t(8;21) AML-M2. Phosphorylation of AML1 on several potential serine and threonine sites, including Ser249, is thought to occur in an Erk-dependent manner.