KIT proto-oncogene, receptor tyrosine kinase (KIT, CD117) and platelet-derived growth factor-alpha (PDGFRA) are key drivers of gastrointestinal stromal tumors (GIST), but resistance to targeted therapy often arises from tumor protein p53 (p53) alterations and loss of cell cycle control. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.