Imatinib mesylate (IM) is applied in GIST patients gradually based on the discovery that GIST is initiated by mutational proto-oncogene KIT or PDGFRA encoding receptor tyrosine kinase, which revolutionizes the management of the disease with its high efficacy, primary resistance observed in only approximately 10% patients [3]. This evidence concerns the gene KIT and gastrointestinal stromal tumor.