PDGFRB and gastrointestinal stromal tumor: The genomic landscape of GIST has been well characterized and GIST may be classified as KIT-mutated (67%), PDGFR-mutated (16%) or GIST without KIT or PDGFR mutations (16-17%) in which other alterations are recognized including NF1, SDH, BRAF or NTRK gene alterations.