PDGFRA and gastrointestinal stromal tumor: Imatinib inhibits the kinase activity of kit, PDGFR-α, and the breakpoint cluster region (BCR)/Abelson (ABL) fusion protein.5 Median overall survival for patients with advanced GIST treated with imatinib was longer than 57 months, compared with 9 months for doxorubicin-treated, historical controls.6,7