The ABL2 gene encodes for a non-receptor tyrosine kinase (TK) with high homology to ABL1. ABL1 and ABL2 proteins belong to the Abelson family and link diverse extracellular stimuli to signaling pathways controlling cell growth, survival, invasion, and migration.

The translocation t(1;12)(q25.2;p13.2) involving ABL2 was shown to result in a chimeric protein consisting of the helix-loop-helix (HLH) domain of ETV6 and the TK domain of ABL2. The HLH domain of ETV6 is known to confer oncogenic activity to chimeric tyrosine kinase proteins by forming ligand-independent oligomers. The ETV6-ABL2 fusion gene has been detected in a patient with AML-M3 and in a T-cell ALL cell line. Further ABL2 fusion partners have been identified in patients with Philadelphia chromosome-like ALL, including PAG1, RCSD1, and ZC3HAV1. Cell lines expressing ABL2 fusions were shown to respond to tyrosine kinase inhibitors. Moreover, a patient with B-ALL positive for RCSD1-ABL2 fusion was reported to respond to treatment with the ABL1 inhibitor imatinib. Hence, detection of ABL2 rearrangements by FISH may help in selecting patients eligible for therapy with TK inhibitors.