A 68-year-old man presents with fatigue, splenomegaly, and peripheral blood showing 40% blasts with Auer rods. Cytogenetics reveal t(8;21)(q22;q22). Which fusion transcript does this translocation produce and what is its prognostic significance in AML?
- A BCR-ABL1; favorable prognosis if treated with imatinib
- B PML-RARA; favorable prognosis, treated with ATRA + ATO
- C RUNX1-RUNX1T1 (AML1-ETO); favorable prognosis with standard cytarabine/anthracycline ✓
- D CBFB-MYH11; favorable prognosis with high-dose cytarabine consolidation
Correct answer: C. RUNX1-RUNX1T1 (AML1-ETO); favorable prognosis with standard cytarabine/anthracycline
Explanation
t(8;21) fuses RUNX1 (AML1) on chromosome 21 with RUNX1T1 (ETO) on chromosome 8, generating RUNX1-RUNX1T1 which functions as a transcriptional repressor blocking myeloid differentiation. Along with inv(16)/t(16;16) producing CBFB-MYH11, this constitutes core-binding factor AML with favorable prognosis (~60–70% OS at 5 years) using high-dose cytarabine consolidation. PML-RARA results from t(15;17) producing APL, which is treated with ATRA+ATO. BCR-ABL1 characterizes CML.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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