Which oncogene mechanism best describes the action of BCL-2 in follicular lymphoma, where it is overexpressed due to the t(14;18) translocation?

• A Constitutive activation of receptor tyrosine kinase signalling
• B Inhibition of apoptosis by blocking cytochrome c release from mitochondria ✓
• C Promotion of cell cycle entry by inhibiting RB1 phosphorylation
• D Transcriptional activation of MYC target genes

Explanation

BCL-2 is an anti-apoptotic protein located on the outer mitochondrial membrane that prevents cytochrome c release by antagonizing pro-apoptotic BAX and BAK proteins. The t(14;18) translocation juxtaposes BCL-2 with the immunoglobulin heavy chain locus, causing constitutive overexpression. This does not accelerate proliferation but rather prolongs cell survival by blocking the intrinsic (mitochondrial) apoptosis pathway, resulting in the indolent accumulation of long-lived B lymphocytes characteristic of follicular lymphoma.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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