Immunofluorescence confocal microscopic analysis revealed that under control conditions, KIT and PDGFRA in GIST-T1 cells were found at the perinuclear region together with Golgi markers (Figs. 1B and S1A) (10, 11, 15); however, these RTKs disappeared from the Golgi region in cells treated with 1 μM M-COPA for 8 h (Fig. 1, B and C). This evidence concerns the gene KIT and gastrointestinal stromal tumor.