system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
All are true about GIST EXCEPT?
assistant
The correct answer is  Ref: Robbins Pathology, 9th ed. pg. 775-76* Majority of gastrointestinal stromal tumors originate from stomach. The cell of origin is interstitial cell of Cajal which are present in muscularispropria.* The useful marker is c-kit (CD 117) detectable in 95% of patients.* PET scan is the imaging modality of choice* Treatment is tyrosine kinase inhibitors like imatinib mesylate.