KIT and gastrointestinal stromal tumor: Interestingly, in GIST‐5R (imatinib resistant) cells, nintedanib was more potent than sunitinib against KIT Y719 phosphorylation, which regulates SCF‐mediated cell migration [36], and both nintedanib and sunitinib displayed profound inhibitory effects on KIT Y703 and Y823 phosphorylation.