In addition to brain tumors, the role of mutant PDGFR has numerously been emphasized in other malignant diseases, like dermatofibrosarcoma protuberans [94], gastrointestinal stromal tumor (GIST) [95], osteosarcoma [96], alveolar rhabdomyosarcoma [97], chronic myeloid leukemia (CML) [98], prostate cancer [99], liver cancer [100], non-small-cell lung cancer [101], and colorectal cancer [102] and in breast cancer [103]. The gene discussed is PDGFRB; the disease is osteosarcoma.