Abstract
Immunohistochemistry (IHC) is an important tool in pathology and allows visualization of antigens when obtaining tissue specimens from patients and employs labeled antibodies directed against those antigens. IHC is helpful to improve tumor classification, identify pathogens and discover prognostic markers when distinguishing features are absent or minimized by morphological assessment. As routine IHC has emerged over the years, monoclonal antibodies and further development of automated stainers allow for increased sensitivity and specificity of antigens assessed by IHC. Since cancer classification relies upon IHC to subtype cancers, define the origin of metastases and to administer targeted therapy, IHC remains a valuable and necessary process for clinical pathology. Innovations continue to be made in IHC, such as new biomarkers, multiplexing and fluorescent technology.