Estrogen Receptor

Estrogen receptor (ER) is a nuclear receptor for estrogens such as estradiol (the main endogenous human estrogen). The two different estrogen receptor proteins produced from the ESR1 and ESR2 genes are usually called the alpha and beta receptors.

This ER antibody recognizes a protein of 67 kDa, which is identified as estrogen receptor (ER) alpha. The ER gene consists of more than 140 kb of genomic DNA divided into 8 exons, which are translated into a protein with six functionally discrete domains, labeled A through F. This antibody strongly stains the nucleus of epithelial cells in breast carcinomas. ER is an important regulator of growth and differentiation of cells in the mammary gland. Presence of ER in breast tumors indicates an increased likelihood of response to anti-estrogen (e.g., Tamoxifen) therapy.

Estrogen receptor clone RBT11 is a rabbit monoclonal antibody derived from cell culture supernatant that is concentrated, dialyzed, filter sterilized and diluted in buffer pH 7.5, containing BSA and sodium azide as a preservative.

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1. Cut and mount 3-4 micron formalin-fixed paraffin-embedded tissues on positive charged slides.
2. Air dry for 2 hours at 58° C.
3. Deparaffinize, dehydrate and rehydrate tissues.
4. Subject tissues to heat epitope retrieval using a suitable retrieval solution such as ImmunoDNA Retriever with Citrate (BSB 0020-BSB 0023) or EDTA (BSB 0030-BSB 0033).
5. Any of three heating methods may be used:
   • Electric Pressure Cooker
     Place standoff rack at base of pressure cooker. Add 1-2 inches of distilled water to the pressure cooker and turn heat to high, and incubate for 15 minutes. Open and immediately transfer slides to room temperature.
   • Water Bath Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a water bath set at 95°-99° C. Incubate for 30-60 minutes.
   • Conventional Steamer Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a Steamer, cover and steam for 30-60 minutes.
6. After heat treatment, transfer slides in ImmunoDNA Retriever with Citrate or EDTA to room temperature and let stand for 15-20 minutes.
7. Wash slides with IHC wash buffer or DI water.
8. Continue IHC staining protocol.