PDGFRB and gastrointestinal stromal tumor: Imatinib mesylate (Gleevec) is a successful PDGFR tyrosine kinase inhibitor for the treatment of some hematological malignant [6], dermatofibrosarcoma protuberans, and Kit+ Gastrointestinal Stromal Tumors (GIST) [7], [8], [9], [10].