Sunitinib and dovitinib lacked activity against secondary mutations in the KIT activation loop (KIT exons 17 and 18), in contrast to regorafenib, sorafenib, nilotinib, ponatinib and dasatinib, which inhibited viability of GIST cells dependent on some or all of the activation-loop mutants (Table 1). Here, KIT is linked to gastrointestinal stromal tumor.