The Philadelphia chromosome t(9;22)(q34;q11) in CML generates BCR-ABL1. The mechanism by which BCR-ABL1 drives leukemogenesis is:
- A Loss of tumor suppressor function causing inability to repair DNA damage
- B Amplification of RAS signaling through guanine nucleotide exchange factors
- C Constitutive activation of tyrosine kinase activity promoting cell survival and proliferation ✓
- D Inhibition of topoisomerase II leading to chromosomal instability
Correct answer: C. Constitutive activation of tyrosine kinase activity promoting cell survival and proliferation
Explanation
BCR-ABL1 encodes a constitutively active tyrosine kinase that continuously phosphorylates substrates in cell survival (PI3K-AKT) and proliferation (RAS-MAPK) pathways and inhibits apoptosis. Unlike normal ABL1, BCR-ABL1 cannot be allosterically autoinhibited. This kinase is the target of imatinib and subsequent tyrosine kinase inhibitors used to treat CML.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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