This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which is the most specific marker for GIST 
Select and explain. 
A. CD 117, B. CD 34, C. DOG 1, D. PDGF alfa mutation
C: DOG 1
Answer: C: DOG 1 
Explanation: CD117 is also known as CKIT is present in 90% of cases