PDGFRA and gastrointestinal stromal tumor: The majority of gastrointestinal stromal tumors (GISTs) are driven by mutation in the KIT proto-oncogene, receptor tyrosine kinase (KIT), and platelet-derived growth factor receptor alpha (PDGFRA) genes, which are proto-oncogenes encoding the cell-surface receptors c-kit and PDGFRA protein in the type III receptor tyrosine kinase (RTK) family.