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 .CD99 (known as MIC2 or E2 antigen) is a cell surface glycoprotein expressed on the surface of cortical thymocytes and subset of mature T- and B-lymphocytes. CD99 is widely used as a marker for Ewing’s sarcoma/PNET family exhibiting a membranous stain. Also expressed in T- and B-ALL, solitary fibrous tumor,T-cell lymphoma, anaplastic large cell lymphoma, AML, GIST, various carcinomas.