This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Pathology
All are true about GIST EXCEPT? 
Select and explain. 
A. Most common mesenchymal tumor of GIT, B. C-kit (CD 117) positive, C. Originate from interstitial cells of Cajal, D. Majority seen in duodenum
D: Majority seen in duodenum
Answer: D: Majority seen in duodenum 
Explanation: 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.