Which chromosomal translocation creates a BCR/ABL1 fusion gene product associated with CML?

Which chromosomal translocation creates a BCR/ABL1 fusion gene product associated with CML?

• A. t(8;22)
• B. t(11;14)
• C. t(9;21)
• D. t(9;22)

Answer: (D)

The key idea is that a translocation between chromosome 9 and 22 creates the BCR-ABL1 fusion gene, the hallmark of chronic myeloid leukemia. This fusion produces a protein with constitutive tyrosine kinase activity, so it sends continuous growth signals that drive the unchecked proliferation of myeloid cells seen in CML. This is also why drugs that inhibit BCR-ABL1, like imatinib, are effective treatments. The other listed translocations do not generate the BCR-ABL1 fusion associated with CML; they are linked to different hematologic malignancies.

The key idea is that a translocation between chromosome 9 and 22 creates the BCR-ABL1 fusion gene, the hallmark of chronic myeloid leukemia. This fusion produces a protein with constitutive tyrosine kinase activity, so it sends continuous growth signals that drive the unchecked proliferation of myeloid cells seen in CML. This is also why drugs that inhibit BCR-ABL1, like imatinib, are effective treatments.

The other listed translocations do not generate the BCR-ABL1 fusion associated with CML; they are linked to different hematologic malignancies.