One PDX model could be established from a tumor sample with a secondary KIT exon 16 mutation and a primary KIT exon 9 mutation (UZLX-GIST73), and an imatinib-resistant PDX model could be established with a primary KIT exon 11 mutation, and secondary KIT exon 11 and exon 17 mutations (UZLX-GIST9). The gene discussed is KIT; the disease is neoplasm.