Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody . CD117 (c-kit) is a member of tyrosine kinase growth factor receptor type III family. CD117 is expressed in gastrointestinal stromal tumours, seminoma, mast cell disease, melanoma, CML, AML, adenoid cystic carcinoma, thymoma and thymic carcinoma. CD 117 is of critical importance in diagnosing of gastrointestinal stromal tumour (GIST) and further to plan-targeted therapy.