Gastrointestinal tract tumours (GIST) develop in the gastrointestinal (GI) tract, which includes the stomach, small intestine, and oesophagus.  GISTs arise from specialized cells called interstitial cells of Cajal, which help regulate the movement of food through the digestive system. 

 

GISTs can occur at any age, but they are more commonly diagnosed in adults. The exact cause of GISTs is unknown, but most cases are associated with certain genetic mutations, particularly in the KIT or PDGFRA genes.