KIT and gastrointestinal stromal tumor: Gastrointestinal stromal tumour (GIST) is a mesenchymal tumour of the gastrointestinal tract and the most common subtype of human sarcoma.1,2 KIT or PDGFRA receptor tyrosine kinase gain-of-function mutations are crucial initiating oncogenic events in 90% of GISTs,3,4 resulting in oncogenic addiction.