After providing evidence that GIST has a distinct identity by sharing features with the interstitial cells of Cajal [2], encoding gain-of-function mutations were found on the c-kit and platelet-derived growth factor-alpha (PDGFR-α) genes [3, 4], now known as hallmarks in tumorigenesis of GIST [5–7]. The gene discussed is PDGFRA; the disease is gastrointestinal stromal tumor.