USMLE Step 1 Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The translocation t(9;22) is associated with Chronic Myeloid Leukemia (CML). This genetic alteration results in the formation of the BCR-ABL fusion gene, which encodes a constitutively active tyrosine kinase. This abnormal tyrosine kinase activity promotes uncontrolled cell division and survival of hematopoietic progenitor cells, leading to the characteristic features of CML.

When this translocation is observed in the context of Acute Lymphoblastic Leukemia (ALL), it is linked to a particularly poor prognosis. The presence of the BCR-ABL fusion gene in ALL indicates a more aggressive disease, reflecting the role of this mutation in enhancing leukemogenesis. Therefore, the strong association between the t(9;22) translocation and CML, as well as its implications for prognosis when seen in ALL, supports the choice of Chronic Myeloid Leukemia in this context.