Breakpoint cluster region-Abelson murine leukemia viral oncogene 1 fusion protein (BCR-ABL1)

The Breakpoint cluster region-Abelson murine leukemia viral oncogene 1 fusion protein (BCR-ABL1) is an abnormal tyrosine kinase generated by a reciprocal translocation between the BCR gene on chromosome 22 and the ABL1 gene on chromosome 9, forming the so-called Philadelphia chromosome[1][2][3]. This oncogenic fusion leads to constitutive tyrosine kinase activity, driving uncontrolled proliferation and survival of hematopoietic cells. Depending on breakpoint locations, it produces several isoforms—most notably p210 (typical for chronic myeloid leukemia), p190 (most common in Ph+ acute lymphoblastic leukemia), and rarely, p230 (associated with chronic neutrophilic leukemia variants)[1][2]. The BCR-ABL1 fusion protein is a validated therapeutic target; its inhibition by tyrosine kinase inhibitors such as imatinib has revolutionized CML treatment. BCR-ABL1 levels, measured by molecular tests, are used as biomarkers for disease monitoring and treatment efficacy[2]. Resistance can occur by kinase domain mutations or mechanisms independent of direct kinase alteration, posing a major therapeutic challenge, especially in acute leukemias[5][6].

Other names

BCR-ABL1 fusion proteinBCR-ABL fusion proteinPhiladelphia chromosome fusion proteinp190 BCR-ABL1p210 BCR-ABL1p230 BCR-ABL1

Tyrosine kinase inhibition