Use

Eighty percent of patients with gastrointestinal stromal tumor (GIST) have a C‑KIT mutation in exon 9, 11, 13, or 17. The presence of a mutation usually predicts poor survival. Patients with C‑KIT mutations other than D816V are likely to respond to imatinib (Gleevec) therapy. Mutations in the PDGFRA gene are found in about 7% of gastrointestinal stromal tumors (GISTs), especially in KIT wild type GISTs. PDGFRA mutations also have been described in synovial sarcomas (SSs) and malignant peripheral nerve sheath tumors (MPNST). GISTs with PDGFRA mutations (except D842V) are likely to respond to imatinib.