Therapeutic strategies for wild-type gastrointestinal stromal tumor: is it different from KIT or PDGFRA-mutated GISTs?
Gastrointestinal stromal tumor (GIST) is the most common and potentially-malignant mesenchymal tumor in the gastrointestinal tract (1,2). GIST may arise at any age although it is frequently reported around the 60s. GISTs are found most often in the stomach, followed by the small intestine, but GISTs may occur at any sites of the gastrointestinal tract and peritoneal cavity including the colon and esophagus. The proliferation of most GISTs (80% to 90%) is driven by gain-of-function mutations either in the KIT or platelet-derived growth factor receptor alpha (PDGFRA) gene, which are mutually exclusive. Surgery is the only potentially-curative treatment for primary GIST. Nearly 40% of GIST patients, however, have had disease recurrence even after complete resection (3). Imatinib mesylate (Gleevec, Novartis Pharmaceuticals, Basel, Switzerland) has revolutionized treatment of advanced and recurrent GISTs by inhibiting the KIT and PDGFRA signaling pathways (4).