The c-Kit pharmDx assay is a qualitative immunohistochemical (IHC) kit system used manually and on the Dako Autostainer, for the identification of c-kit protein/CD117 antigen (c-kit protein) expression in normal and neoplastic formalin-fixed paraffin-embedded tissues for histological evaluation. The c-Kit pharmDx rabbit polyclonal antibodies specifically detect the c-kit protein in CD117 antigen-expressing cells. This test is indicated as an aid in the differential diagnosis of gastrointestinal stromal tumors (GIST).