CSF1R and gastrointestinal stromal tumor: Scant biomarker-targeted therapies currently approved by the Food and Drug Administration (FDA) for sarcomas are those for KIT and PDGFRA in gastrointestinal stromal tumors (GIST), CSF1R in tenosynovial giant cell tumor, EZH2 in epithelioid sarcoma, mTOR in perivascular epithelioid cell differentiation tumors (PEComa), and ALK in inflammatory myofibroblastic tumor (4, 7–10).