PDGFRB and gastrointestinal stromal tumor: Sunitinib malate (Sutent®) is an oral multitargeted receptor tyrosine kinase inhibitor with selectivity for KIT and PDGFRA (and for PDGFRB, all three isoforms of vascular endothelial growth factor receptor, FMS-like tyrosine kinase 3, colony-stimulating factor 1 receptor and glial cell line-derived neurotrophic factor receptor) [6], whose administration is associated with a significant improvement in PFS (27.6 vs 6.4 weeks with placebo, P < 0.0001) for metastatic GIST patients progressing on imatinib.