Of these cases, 20–40% are characterized by the loss of SDHB (SDH-deficient GIST)2–4, approximately 15% carry BRAF/RAS or NF1 mutations, and the remaining cases are designated as KIT/PDGFRA/SDH/RAS-P WT GISTs (or quadruple WT GISTs) in which the molecular driver alterations are still unknown. The gene discussed is PDGFRA; the disease is gastrointestinal stromal tumor.