Amplifications, mutations, and rearrangements of platelet-derived growth factor (PDGF) and its receptor PDGFR have been implicated in the pathophysiology of multiple tumor types including gastrointestinal stromal tumor (GIST), glioblastoma, and dermatofibrosarcoma protuberans [17–19]. This evidence concerns the gene PDGFRB and gastrointestinal stromal tumor.