A 52-year-old woman has a follicular lymphoma. The neoplastic cells show a t(14;18) translocation resulting in overexpression of an anti-apoptotic protein that keeps cytochrome c sequestered within mitochondria. Which protein is overexpressed?
- A BAX
- B BCL-2 ✓
- C p53
- D Cytochrome c
Correct answer: B. BCL-2
Explanation
The t(14;18) translocation places the BCL-2 gene under control of the immunoglobulin heavy chain promoter, causing constitutive BCL-2 overexpression in follicular lymphoma. BCL-2 resides in the mitochondrial outer membrane and prevents BAX and BAK mediated permeabilization, so cytochrome c stays intramitochondrial and the intrinsic apoptotic signal is blocked. BAX is pro-apoptotic, p53 induces apoptosis by transcriptional targets such as BAX and PUMA, and cytochrome c itself is not overexpressed.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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