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: Pharmacology
[{'content': 'Imatinib is useful in treatment of ? \nSelect and explain. \nA. Neuro fibromatosis, B. CD 117 positive GIST, C. Neuroendocrine tumor of pancreas, D. Breast Ca', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., CD 117 positive GIST GIST cells are positive for CD-1I7 (C-KIT). o Mutation in C-KIT results in continuous activation of receptor tyrosine kinase. o Imatinib inhibits tyrosine kinase activity of C-KIT --> Imatinib is used in GIST o Patients who develop resistance to imatinib may respond to the multiple tyrosinase kinase inhibitor sunitinib.", 'role': 'assistant'}]