A 55-year-old patient with chronic myeloid leukemia (CML) with t(9;22) translocation is started on imatinib. The target of imatinib is:

• A BCR-ABL tyrosine kinase, competitively blocking its ATP-binding site ✓
• B HER2/neu tyrosine kinase receptor, inhibiting downstream RAS signaling
• C Vascular endothelial growth factor receptor, reducing angiogenesis
• D mTOR serine-threonine kinase, blocking translation of proliferative signals

Explanation

Imatinib (Gleevec) is a selective tyrosine kinase inhibitor that competitively occupies the ATP-binding pocket of the BCR-ABL fusion kinase produced by the Philadelphia chromosome t(9;22) translocation in CML. This prevents phosphorylation of downstream signaling proteins, arresting proliferation and inducing apoptosis in leukemic cells. Imatinib also inhibits c-KIT (relevant in GIST) and PDGFR; its selectivity profile makes it a prototype for targeted cancer therapy.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.