Cytogenetic analysis of bone marrow from a 4-year-old girl with precursor B-cell acute lymphoblastic leukemia reveals a balanced translocation involving chromosomes 12 and 21. Which statement regarding this finding is correct?

• A It generates the ETV6-RUNX1 fusion and carries a favorable prognosis ✓
• B It generates the BCR-ABL1 fusion and predicts resistance to vincristine
• C It involves KMT2A at 11q23 and is typical of infantile leukemia
• D It defines hypodiploidy and is associated with early relapse

Explanation

t(12;21)(p13;q22) produces the ETV6-RUNX1 (formerly TEL-AML1) fusion, the commonest cytogenetic abnormality in childhood B-ALL and a marker of excellent response to standard therapy. In contrast, BCR-ABL1 and KMT2A (MLL) rearrangements are high-risk lesions, and hypodiploidy, not this translocation, defines the poor-risk numeric subgroup. Recognizing favorable versus adverse ALL genetics is a recurring examination theme.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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