Tissue or Cell-Based Techniques

Immunohistochemistry (IHC) is a commonly used method to identify the lineage or histogenesis of tissue cells in paraffin-fixed processed tissue. Various methods are employed to bind a chromogen to a target epitope within the tissue (Table 14.1). The chromogens attach via antibody-binding or protein–ligand binding utilizing avidin–biotin or streptavidin–biotin affinities. Commonly used chromogen methods employ alkaline phosphatase (AP) or horseradish peroxidase (HRP), resulting in a red or brown chromogen.