ABL2 (ARG, Abl-related gene), together with c-Abl, forms the Abl family of mammalian non-receptor tyrosine kinases. ABL2 and c-Abl share 89%, 90 and 93% identity in their SH3, SH2 and tyrosine domain, but only 29% identity in the carboxy-terminal half. The human c-Abl and ABL2 genes are expressed ubiquitously. ABL2 had been detected predominantly in the cytoplasm, whereas c-Abl shows both cytoplasmic and nuclear localization. c-Abl is involved in two different chromosomal translocations present in human leukemias, which generate Bcr-Abl and TEL-Abl. Recently, TEL-ARG fusion transcripts have also been identified in acute myeloid leukemias (AML). The Abl family kinases may also interact with receptor tyrosine signaling pathways and regulate cellular function such as cell cycle progression, gene transcription and organization of the actin cytoskeletons in neurons.