Drug of choice in chronic myeloid leukemia:
**Core Concept**
Chronic myeloid leukemia (CML) is a type of cancer characterized by the uncontrolled growth of myeloid cells in the bone marrow. The disease is often associated with a specific chromosomal abnormality, the Philadelphia chromosome, which results from a reciprocal translocation between chromosomes 9 and 22. This translocation creates a fusion gene, BCR-ABL, which encodes a tyrosine kinase enzyme that contributes to the development and progression of CML.
**Why the Correct Answer is Right**
The drug of choice in CML is a tyrosine kinase inhibitor (TKI) that targets the BCR-ABL enzyme. Imatinib, a first-generation TKI, was the first drug to be approved for the treatment of CML. It works by binding to the ATP-binding site of the BCR-ABL enzyme, thereby inhibiting its activity and preventing the proliferation of malignant cells. Imatinib has been shown to be highly effective in inducing and maintaining complete hematologic and cytogenetic responses in patients with CML.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not represent a standard treatment for CML.
**Option B:** This option is incorrect because it is not a targeted therapy for CML.
**Option C:** This option is incorrect because it is not a commonly used treatment for CML.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the treatment of CML has evolved significantly over the years, with the introduction of newer TKIs such as dasatinib and nilotinib, which have shown improved efficacy and tolerability compared to imatinib. Additionally, the use of TKIs has revolutionized the management of CML, allowing for the achievement of deep and sustained responses in many patients.
**Correct Answer: C. Imatinib**