The BCR-ABL fusion gene in chronic myeloid leukemia results from the Philadelphia chromosome, t(9;22). The constitutively active BCR-ABL protein drives oncogenesis primarily through which enzymatic activity?

• A Serine/threonine kinase
• B Histone deacetylase
• C GTPase
• D Tyrosine kinase ✓

Explanation

BCR-ABL encodes a fusion protein with constitutively active tyrosine kinase activity, driving proliferation through downstream pathways such as JAK-STAT, RAS-MAPK, and PI3K-AKT. Imatinib and other tyrosine kinase inhibitors specifically target this activity. Option A is wrong because BCR-ABL is not a serine/threonine kinase. Option C describes RAS, not BCR-ABL. Option B is unrelated to BCR-ABL function.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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