<prompt> Imatinib is useful in treatment of ?Neuro fibromatosisCD 117 positive GISTNeuroendocrine tumor of pancreasBreast Ca  <response>: 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. 