Estrogen/Progesterone Receptor Assay

What sample is needed for the Estrogen/Progesterone Receptor Assay?

1. Breast cancer tissue blocks are needed.
2. Fresh tumor cells to get slices of cytoplasm (Cytosol).

What are the Indications for the estrogen/progesterone receptor assay?

1. ER is done on the breast cancer tissue to evaluate the hormone response.
2. ER also indicates the prognosis.

What are the reasons for False-negative ER receptors?

1. Incorrect handling and storage of tissue samples lead to degradation of thermolabile receptor proteins.
2. If the protein concentration in the sample being assayed is low.
3. If a biopsy is taken from the surrounding normal tissue.

How will you describe the Pathophysiology of the Estrogen/Progesterone Receptor Assay?

1. The estrogen receptor is a specific cellular protein with high affinity and specificity for the Estrogen hormone.
2. The estrogen receptor protein is found in target tissues such as the breast, uterus, pituitary gland, and hypothalamus.
3. Estrogen stimulates the cells through the Estrogen receptor.
4. A reduction in the blood estrogen level reduces the biochemical activity of these cells.
5. This is the basis for the treatment of breast cancer by anti-hormone therapy.
6. ER-positive breast cancer is twice as responsive as ER-negative cases.

7. Postmenopausal women’s breast cancers are more ER-positive than those of young women.
8. ER-positive tumors have a better prognosis than ER-negative cases.
9. More than 50% of ER-positive cases respond to anti-hormone therapy (Tamoxifen).
10. In metastatic carcinoma of the breast, 1/3 of the women have various types of endocrine therapy directed at lowering their estrogen level, e.g.
    1.  Oophorectomy.
    2. Hypophysectomy.
    3. Adrenalectomy (ablation therapy).
    4. Anti-estrogen and androgen (additive therapy).

What is the significance of the ER/PR receptor?

1. PR receptor is useful for assaying ER receptors.
2. Metastatic cancer with ER and PR receptor-positive tumors has a response rate of 75% to endocrine therapy.
3. If the ER-positive and PR-negative tumors have a 40% response rate.
4. If the ER-negative and PR-positive patients’ only response rate to endocrine therapy is 25%.
5. In cases where ER and PR are negative, the response rate is only 5%.
6. The percentage of positive cases in postmenopausal women is more significant than in premenopausal women.

What are the procedures for Estrogenprogesteron Receptor Assay Detection?

1. Mostly, ER testing is performed on cancer tissue (paraffin blocks) using immunohistochemistry.
2. Another method can be an enzyme immunoassay.
3. Chromatography techniques.
4. EIA.

What is the normal estrogen/progesterone receptor assay (tissue)?

• Negative = <3 fmol/mg cystosol protein.
• Borderline = 3 to 9 fmol/mg cytosol protein.
• Positive = >10 fmol/mg cytosol protein.

How will you interpret immunocytochemistry slides for ER/PR?

1. Negative = <5 % of the nuclei of the cells for the receptors.
2. Positive = >5 % of the nuclei of the cells stain for the receptors.

What is ER/PR positivity?

1. Carcinoma of the breast (60%) shows positivity.
2. Approximately 2/3 of the cases show a response to hormone therapy.
3. In ER-negative cases, 90% do not respond to hormone therapy.
4. The hormone receptor positivity varies in different patients:
   1. ER⁺ = 80% of the cases.
   2. ER⁺ PR⁺  = 65% of the cases.
   3. ER⁺ PR^–  = 13% of the cases.
   4. ER^–  PR⁺  = 2% of the cases.
   5. ER^–  PR^–  = 25% of the cases.

How will you interpret ER/PR positivity?

1. Favorable response >20% cell stain.
2. The borderline response is 11% – 20% of the cell stain.
3. The unfavorable response is <10% cell stain.
4. ASCO guidelines are:
   1. Positive for ER/PR if  ≥ 1% of the tumor cell nuclei are immunoreactive.
   2. Negative ER/PR if  <1% of tumor cell nuclei are immunoreactive.
5. Allred scoring: This replaced the early scoring system.
   1. ER-positive tumor cells have >10% positive cells.
   2. ER-negative tumor cells are 1% – 9% positive.

How will you score the tumor cells?

6. Progesterone receptors (PRs) should be tested alongside ER. Because PR depends upon estrogen activity.
7. PR positivity confirms that all ER steps were performed correctly.
8. When ER/PR is positive, the tumor response to treatment is 75%.

Response to anti-hormone therapy

Estrogen/Progesterone Receptor Assay: The brown color indicates a positive reaction (ER-positive cells)

Questions and answers: