As shown in Table 1, the IC50 values for VEGFR inhibitors in the GIST 430 cell line were significantly (~3- and 5-fold) higher for regorafenib and sunitinib, respectively, when compared with GIST T1-R cells, whereas the IC50 values of IM for both of the IM-resistant GIST cells were almost the same, thereby illustrating that different molecular pathways are able to maintain similar levels of resistance to this targeted drug. This evidence concerns the gene KDR and gastrointestinal stromal tumor.