A 4-year-old presents with pallor, petechiae, and hepatosplenomegaly. CBC shows Hb 6 g/dL, WBC 65,000/µL with 80% blasts, platelets 18,000/µL. Blast immunophenotype shows CD10+, CD19+, TdT+, and CD34+. Cytogenetics reveals t(12;21)(p13;q22) translocation [ETV6-RUNX1]. What is the prognostic implication of this finding?

• A This is a high-risk translocation associated with poor prognosis similar to t(9;22)
• B This translocation is neutral and prognosis depends only on WBC count at diagnosis
• C This translocation requires allogeneic stem cell transplantation in first remission
• D This is a favourable-risk translocation associated with excellent prognosis; 5-year EFS ~90% ✓

Explanation

The t(12;21)(p13;q22) creating the ETV6-RUNX1 (TEL-AML1) fusion is the most common translocation in paediatric B-ALL, found in ~25% of cases. It is associated with favourable prognosis — 5-year event-free survival approaches 90% with standard chemotherapy. The fusion protein impairs normal haematopoiesis and is highly sensitive to standard ALL protocols. This contrasts with t(9;22) [BCR-ABL1/Philadelphia chromosome], which is a high-risk finding requiring tyrosine kinase inhibitor addition and often transplant consideration.

Reference: Ghai Essential Pediatrics, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.