Our loss-of-function studies targeting Wee1 in an isogenic pair of cell lines driven by KIT (GIST-T1+Cas9) or PDGFRA (GIST-T1+D842V KITKO) revealed an essential role for Wee1 in GIST cell proliferation, suggesting Wee1 as a plausible drug target in GISTs. Here, KIT is linked to gastrointestinal stromal tumor.