XL ABL2 BA consists of an orange-labeled probe hybridizing proximal to the breakpoint in the ABL2 gene region at 1q25.2 and a green-labeled probe hybridizing distal to the break point in the ABL2 gene region at 1q25.2.

Probe maps are created in accordance with the intended purpose of the product. Solid colored bars do not necessarily indicate that the probe fully covers the indicated genomic region. Therefore, caution is advised when interpreting results generated through off-label use. Probe map details based on UCSC Genome Browser GRCh37/hg19. Map components not to scale. Further information is available on request.

Acute lymphoblastic leukemia (ALL) is a rare disease with approximately 1:100.000 new diagnoses per year. Around 3-5% of pediatric ALL and 25% of adult ALL are characterized by t(9;22), resulting in the BCR-ABL1 fusion gene, a constitutively active tyrosine kinase. Furthermore, BCR-ABL1 is genetically characterizing chronic myelogenous leukemia. Tyrosine kinase inhibitor treatment of BCR-ABL1-positive cases, which initially have a poor prognosis, dramatically improves the outcome. A novel high risk subtype called BCR-ABL1-like ALL or Philadelphia-like ALL was discovered based on similar gene expression profiles to BCR-ABL1-positive ALL and is characterized by aberrations resulting in activation of tyrosine kinase signaling pathways. Prominent genes in the JAK/STAT activating group are CRLF2, EPOR and JAK2, while members of the ABL-class fusions are ABL1, ABL2, CSF1R and PDGFRB. ´The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia´ specifies B-lymphoblastic leukemia/lymphoma, BCR-ABL1–like as a provisional entity.
The ABL2 gene has been initially identified as a novel fusion partner of ETV6. ABL2 belongs to the Abelson family of non-receptor tyrosine kinases and is highly similar to ABL1. t(1;12)(q25;p13) results in a chimeric ETV6-ABL2 protein with a constitutive active tyrosine kinase.

Clinical Applications

• Acute Lymphoblastic Leukemia (ALL)

XL ABL2 BA hybridized to HT-93 cells carrying t(1;12) and t(15;17), one interphase is shown. The separation of one colocalization/fusion signal indicates a split of the orange and green labled probes flanking the ABL2 breakpoint region. The remaining copy of ABL2 contributes one colocalization/fusion signal. The additional orange signal was interpreted to be localized on a derivative chromosome 4 representing a duplication of parts of the q-arm of the derivative chromosome 1.

• Iijima et al (2000) Blood 95:2126-2131
• Arber et al (2016) Blood 127:2391-2405
• Tasian et al (2017) Blood 130:2064-2072