BCR-ABL

The translocation between BCR-ABL1 or Philadelphia chromosome translocation is a genetic alteration typically present in the majority of patients with Chronic Myeloid Leukemia (CML) and some patients with Acute Lymphoblastic Leukemia (ALL).

The fusion of the BCR genes, located on chromosome 22, and ABL1, located on chromosome 9, results in an oncogene that produces an abnormal protein. This abnormal protein leads to increased tyrosine kinase activity, causing abnormal and uncontrolled growth of lymphocytes, ultimately leading to leukemia.