Establishment and characterization of a novel xenograft model of human gastrointestinal stromal tumor in mice

Background: The clinical outcome of gastrointestinal stromal tumor (GIST) has been improved by the introduction of molecular-targeting drugs. However, resistance to these drugs appears during the course of treatment. The aim of this study was to establish and characterize a human xenograft model of GIST. Materials and Methods: GIST tissue from a patient with esophageal GIST was implanted under the skin of a NOD-SCID mouse. The tumor became successfully engrafted and we investigated the effects of imatinib and sunitinib on this model. KIT mutation was investigated by complementary DNA analysis, and c-KIT (CD117) expression was evaluated by immunohistological staining. Results: cDNA analysis of the tumor revealed a KIT mutation in exon 11. c-KIT expression was observed in each passaged tumor. Both imatinib and sunitinib significantly reduced the size of the xenograft tumor. Conclusion: We established a novel xenograft model of human GIST in mice. This xenograft model may be useful for studying GIST.