The vast majority of KIT mutations are found in exon 11 coding for juxtamembrane (66%–71%), exon nine coding for extracellular domain (13%), exon 13 coding tyrosine kinase domain I (ATP binding pocket) (1%–3%), and exon 17 coding for tyrosine kinase domain II (activation loop) (1%–3%), according to reports of various mutation hotspots within the larger group of KIT-mutated GIST (Blay et al., 2021; Zook et al., 2017). The gene discussed is KIT; the disease is gastrointestinal stromal tumor.