Immunohistochemistry, using the basic principles of immunology - the antigen-antibody reaction, namely antigen and antibody specific binding principle, by chemical reaction of the labeled antibody reagent (luciferase, an enzyme, metal ions, isotopes) to confirm the antigens (peptides and proteins) in tissues, its location, qualitative and quantitative research, called immunohistochemistry (immunohistochemistry) or immunocytochemistry techniques (immunocytochemistry).It combined the specific of immune response with visibility of histochemistry by means of a microscope (including fluorescence microscopy, electron microscopy) imaging and amplification, detection of various antigens in a cell, subcellular level, such as proteins, polypeptides, enzymes, hormones, pathogens, and receptors. Immunohistochemical techniques have developed rapidly in recent years. It was limited to immunofluorescence techniques in 1950s, but gradually developed after the 1950s to establish a highly sensitive and more practical immunization enzyme technology.
Immunohistochemistry (IHC) is an important application of monoclonal and polyclonal antibodies, in order to determine the distribution of the target protein in the of health and disease tissue. IHC is widely used for diagnosis of cancers; specific tumor antigens are expressed de novo or up-regulated in certain cancers.