In follicular lymphoma, the t(14;18) translocation results in overexpression of BCL2 within germinal centre B cells. What is the functional consequence of this event?

• A Constitutive JAK-STAT signalling through a cytokine receptor
• B Activation of NF-kB independent of antigen receptor signalling
• C Dysregulation of somatic hypermutation leading to rapid proliferation
• D Blocking of mitochondrial apoptosis, allowing survival of cells that should undergo programmed death ✓

Explanation

t(14;18) moves the anti-apoptotic BCL2 gene to the IgH enhancer locus, so germinal centre cells that would normally die by apoptosis after failing affinity selection survive indefinitely. This explains why neoplastic follicles stain strongly for BCL2 whereas reactive germinal centres are BCL2 negative, a key diagnostic distinction. NF-kB activation independent of antigen signalling is the mechanism of API2-MALT1 in extranodal marginal zone lymphoma.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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