Q. A 54-year-old man comes to his physician’s office for worsening fatigue and abdominal discomfort for the past few months. His temperature is 98.4°F (36.8°C), heart rate is 90/min, respiratory rate is 14/minute, and blood pressure is 130/80 mm of Hg. Physical examination shows a mild splenomegaly. Laboratory studies are shown below. The peripheral blood smear demonstrates the presence of increased mature and immature granulocytes, basophilia, and few myeloblasts. Cytogenetic analysis shows the presence of chromosome translocation t(9;22)(q34;q11.2). What is the mode of action of the drug that is used to treat his condition?