In AML3, which cytogenetic abnormality is observed?

In AML3, which cytogenetic abnormality is observed?

• A. t(8;21)
• B. inv(16)
• C. t(9;22)
• D. t(15;17)

Answer: (D)

Acute promyelocytic leukemia (AML M3) is defined by a specific chromosomal rearrangement: the translocation t(15;17), which creates the PML-RARα fusion gene. This fusion protein disrupts retinoic acid receptor signaling, blocking the maturation of promyelocytes. Treatments that target this abnormal receptor, such as all-trans retinoic acid (ATRA), promote differentiation and lead to effective remission when used appropriately. This translocation is the hallmark cytogenetic feature of AML M3, which is why it’s the correct answer. Other common AML-associated abnormalities map to different subtypes (for example, t(8;21) to AML M2 and inv(16) to AML M4Eo), so they do not define AML3.

Acute promyelocytic leukemia (AML M3) is defined by a specific chromosomal rearrangement: the translocation t(15;17), which creates the PML-RARα fusion gene. This fusion protein disrupts retinoic acid receptor signaling, blocking the maturation of promyelocytes. Treatments that target this abnormal receptor, such as all-trans retinoic acid (ATRA), promote differentiation and lead to effective remission when used appropriately. This translocation is the hallmark cytogenetic feature of AML M3, which is why it’s the correct answer.

Other common AML-associated abnormalities map to different subtypes (for example, t(8;21) to AML M2 and inv(16) to AML M4Eo), so they do not define AML3.