Four of the six patients who restarted imatinib did not have disease progression during a median follow-up of 31 months (range, 19–39 months), whereas one patient with a KIT exon 9 mutation and another patient with a KIT exon 11 mutation had GIST progression 18 and 26 months after imatinib restart, respectively. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.