Each antibody used with IHC has a specific target and staining pattern. The particular location where the precipitation of the chromogen (colored end product) occurs is frequently referred to as its localization or staining pattern. The staining pattern and intensity of the reaction are assessed within the context of the tissue morphology, which is examined and evaluated microscopically only by a qualified pathologist.
Both estrogen receptor (ER) and progesterone receptor (PR) are localized within the nucleus. HER2 antibody is localized within the cell membrane and is described as a membranous stain.
