PDGFRA and gastrointestinal stromal tumor: GI stromal tumors (GISTs) are the most common malignant neoplasm of mesenchymal origin.1 GISTs predominantly originate in the stomach (60%) and small intestine (30%) although they can arise virtually at any portion of the GI tract.1,2 In the late 1990s, the understanding of the essential role of receptor tyrosine kinases KIT or PDGFRA in GIST oncogenesis together with the use of targeted agents such as first-line imatinib marked a new era in GIST therapeutics.3,4