Single agent therapy with small molecule TKIs is effective in malignancies dependent on mutated constitutively activated RTKs [e.g. Kit/a-PDGFR in GIST (IM, Sunitinib), EGFR in NSCLC and GBM (Erlotinib)] and non-RTKs such as, Bcr-Abl in CML (IM, Dasatinib). Here, PDGFRB is linked to gastrointestinal stromal tumor.