**3.1. KIT-mutant GIST**

Though 95% of GISTs are positive for KIT, only 60–85% have mutations in KIT. The most common mutations encountered are mutations of exon 11 (juxtamembrane domain) [4] which is found in about two-thirds of GISTs. Exon 9 (extracellular domain) is less common (9–20%) and is principally correlated with GIST of the small bowel and has a greater malignant potential [4, 33].
