In imatinib-resistant GIST 430 cells, the levels of phosphorylated KIT and its downstream components AKT and STAT3 were significantly downregulated after the treatment with HQP1351 at 0.1 and 0.4 μM for 24 or 72 h (Fig. 3b). Here, STAT3 is linked to gastrointestinal stromal tumor.