A 55-year-old presents with painless cervical lymphadenopathy and night sweats. Biopsy shows a follicular architecture with small cleaved lymphocytes; BCL2 protein is overexpressed. The chromosomal translocation responsible places BCL2 under control of which promoter?
- A MYC gene promoter on chromosome 8
- B Immunoglobulin heavy chain gene promoter on chromosome 14 ✓
- C Cyclin D1 promoter on chromosome 11
- D BCL6 promoter on chromosome 3
Correct answer: B. Immunoglobulin heavy chain gene promoter on chromosome 14
Explanation
Follicular lymphoma is characterized by t(14;18), which juxtaposes BCL2 on chromosome 18 to the immunoglobulin heavy chain (IgH) locus on chromosome 14. The strong IgH promoter drives constitutive BCL2 overexpression, preventing apoptosis. MYC rearrangements with IgH cause Burkitt lymphoma; Cyclin D1/IgH t(11;14) causes mantle cell lymphoma; BCL6 rearrangements are seen in diffuse large B-cell lymphoma.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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