In the GIST-RX4 model, we did not observe any significant differences in the phosphorylation levels of KIT, AKT, and mTOR pathway between the vehicle and TKI-treated groups, although some animals showed a reduction in p-S6 and p-ERK following sunitinib and regorafenib treatment (Figure 4C). Here, KIT is linked to gastrointestinal stromal tumor.