A 40-year-old man has AML with 30% blasts, monocytic components, and eosinophils containing both large basophilic and coarse purple granules on the smear. Cytogenetics show inv(16)(p13q22). Which fusion transcript results from this rearrangement?
- A KMT2A-AFF1
- B RUNX1-RUNX1T1
- C CBFB-MYH11 ✓
- D DEK-NUP214
Correct answer: C. CBFB-MYH11
Explanation
inv(16)(p13q22) fuses the CBFB gene with MYH11, encoding a smooth muscle myosin heavy chain fusion that disrupts core binding factor function. This defines AML with inv(16), formerly FAB M4Eo, recognized morphologically by abnormal eosinophils with mixed basophilic and large violet granules. RUNX1-RUNX1T1 results from t(8;21), the other core binding factor leukemia, and KMT2C fusions occur with 11q23 rearrangements.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.