[GIST refractory to imatinib treatment].

After the introduction of imatinib, the outcome for patients with advanced gastro-intestinal stromal tumor (GIST) was vastly improved. However, resistance to imatinib has become a new problem. The cause of resistance to imatinib is the low sensitivity of gene mutations in the KIT gene or PDGFRα, or an acquisition of additional mutations, and a low plasma level of imatinib. Sunitinib is the first drug that showed an effectiveness for treating GIST refractory to imatinib. New molecular target drugs for overcoming imatinib resistance are being developed now.