To validate the results derived from the gastric GISTs, 11 patients with metastatic small intestinal GISTs (six with KIT exon 11 deletion mutations, one with a KIT exon 13 missense mutation, one with a KIT exon 17 missense mutation, two with KIT exon 9 duplication mutations, and one wild-type GIST) with known clinical outcomes after treatment with imatinib were investigated further. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.