Immunohistochemistry (IHC) is that the commonest application of immunostaining. It involves the method of selectively identifying antigens (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 regard to antibodies utilized in the procedure, and "histo", meaning tissue (compare to immunocytochemistry). Albert Coons conceptualized and first implemented the procedure in 1941. Immunohistochemical staining is widely utilized in the diagnosis of abnormal cells like those found in cancerous tumors. Specific molecular markers are characteristic of particular cellular events like proliferation or necrobiosis (apoptosis). Immunohistochemistry is additionally widely utilized in basic research to know the distribution and localization of biomarkers and differentially expressed proteins in several parts of a biological tissue. Preparation of the sample is critical to take care of cell morphology, tissue architecture and therefore the antigenicity of target epitopes. This needs proper tissue collection, fixation and sectioning. an answer of paraformaldehyde is usually wont to fix tissue, but other methods could also be used.