KIT and gastrointestinal stromal tumor: Recently, we reported that endocytosis of Kit(mut) can be blocked by pitstop2 and filipin, which inhibit clathrin-mediated endocytosis and non-clathrin endocytosis, respectively.34, 39, 40 In GIST-T1, endocytosis inhibition for 24 h did not affect either the Golgi localization of Kit or its phosphorylation (Figure 4a), indicating that the major pathway is early secretion.