KIT and gastrointestinal stromal tumor: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the digestive tract and commonly occur in the stomach and small intestine.1 The molecular characteristics of GISTs include KIT or platelet-derived growth factor receptor alpha (PDGFRA) mutations as single driver mutations, which are detectable in >90% of cases.1 These unique characteristics are associated with the dramatic improvement of clinical outcomes after the introduction of tyrosine kinase inhibitor (TKI).1