CD117

c-KIT, or CD117, is a receptor tyrosine kinase protein that in humans is encoded by the KIT gene. Activating mutations in this gene are associated with gastrointestinal stromal tumors, testicular seminoma, mast cell disease, melanoma, acute myeloid leukemia and small cell lung cancer. CD117 IHC may be used to determine eligibility for treatment with imatinib mesylate (Gleevec®). CD117 is useful in the diagnosis of GISTs, which are positive for CD117, but negative for markers such as desmin and S-100.