Immunohistochemistry (IHC) refers to the process of detecting antigens (e.g. proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno", in reference to antibodies used in the procedure, and "histo," meaning tissue (compare to immunocytochemistry). The procedure was conceptualized and first implemented by Albert Coons in 1941.