Treatment with TAS-116 or 17-AAG decreased Golgi-localised KIT in both IM-naïve GIST T1 and IM-resistant GIST R8 cells, but KIT remained to be co-localised with PDI (ER) in HSP90-inhibited cells (Fig. 2a, b). This evidence concerns the gene HSP90AA1 and gastrointestinal stromal tumor.