In the imatinib-sensitive GIST T1 cells harboring primary KIT mutations, the levels of phosphorylated KIT, AKT, SRC and ERK1/2 were significantly decreased after the treatment with HQP1351 at 0.02 and/or 0.04 μM for 24 or 72 h. Here, MAPK3 is linked to gastrointestinal stromal tumor.