Which drug is known to be effective in treating GIST, and what is its mechanism of action?

Imatinib, commonly known as Gleevac, is particularly effective in treating gastrointestinal stromal tumors (GISTs) because of its specific action on the c-KIT receptor. GISTs often harbor mutations in the c-KIT gene, which encodes a receptor tyrosine kinase that is crucial for the proliferation and survival of these tumor cells. By inhibiting the activity of the mutated c-KIT, Imatinib effectively disrupts the signaling pathways that lead to tumor growth and survival.

In GIST treatment, the drug targets the altered c-KIT receptor directly, reducing the tumor's ability to grow and metastasize. This targeted approach minimizes damage to normal cells and leads to improved patient outcomes compared to less specific therapies.

Sunitinib is also mentioned but functions as a broader multi-targeted receptor tyrosine kinase inhibitor, affecting various pathways and not specifically tailored to the c-KIT mutation. The other options, while representing significant drugs in the oncology landscape, do not directly address the underlying mutation that drives GIST, making the action of Imatinib on c-KIT particularly poignant in this context.