Health Encyclopedia


Tests & Procedures

Immunohistochemical Test for Estrogen and Progesterone Receptors

Immunohistochemical Test for Estrogen and Progesterone Receptors

Does this test have other names?

IHC testing

What is this test?

This test looks for several types of receptors on cells in a sample of breast cancer tissue.

Fifty to 70 percent of breast cancers depend on the hormone estrogen to grow. A few breast cancers can grow without estrogen. The cancer cells that depend on estrogen make many estrogen receptors (ER), progesterone receptors (PR), or both. These receptors grab onto the hormones that float freely in your blood and use them as fuel to help the cancer grow.

Cancers that contain ERs are called ER-positive (ER+). Cancers that contain PRs are called PR-positive (PR+).  Cancers with these types of receptors are called "hormone responsive" cancers.

The immunohistochemical (IHC) test also looks for cell receptors that hold onto HER2, or human epidermal growth factor type 2. HER2 is a protein that is found in excessive amounts in about 20 percent of breast cancers. HER2-positive cancers have many receptors that hold HER2 and are more aggressive than cancers that don't have a lot of HER2.

Before your health care provider can figure out what type of cancer treatment is best for you, he or she must look at the ERs and PRs and know your HER2 status.

To do this, your doctor sends the tissue sample to a lab, where a pathologist runs tests on the tissue sample and looks at the cells under a microscope.

Why do I need this test?

You might have this test if you have breast cancer and your doctor needs more information about the type of breast cancer you have.

If you have a hormone responsive cancer, you will most likely be helped by treatments that will block estrogen from attaching to the receptors or that will lower total estrogens in your system. If you are HER2-positive, you will be offered treatment with the drug Herceptin. 

What other tests might I have along with this test?

Your doctor may also order other tests to help diagnose and treat your breast cancer. These tests include:

  • Blood tests. A complete blood count, or CBC, will check to see whether your blood counts are normal. Chemical and enzyme tests will check to see whether your organs are working the way they should.

  • 21-gene. This test, also called Oncotype DX, will help your health care provider decide whether you need chemotherapy.

  • Lymph node needle biopsy. It's common for breast cancer to spread to nearby lymph nodes. If your health care provider feels that your lymph nodes are enlarged or different in any way, he or she will do a needle biopsy. Whether the nodes are positive for cancer will help your doctor figure out or refine your treatment plan.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.

If your results are positive for estrogen receptors, it means you are ER+. If your results are positive for progesterone receptors, it means you are PR+. In either case, hormone, or endocrine, therapy will likely decrease the chance that your cancer will grow or return. If your tumor, or tissue sample, does not show hormone receptors, you are ER-negative, PR-negative, or negative for both. In that case, hormone therapy will most likely not be helpful to you.

IHC results for HER2 are reported as 0, 1+, 2+, or 3+. A result of 0, 1+, or 2+ is considered HER2-negative (HER2-); a result of 3+ is considered HER2-positive (HER2+). 

Your doctor will review your results together to figure out the best therapy for you. It could be hormone therapy, chemotherapy, or other drugs that target HER2.

How is this test done?

This test requires a sample of tissue. Most often the tissue is taken from the suspicious area of your breast during a biopsy procedure. A biopsy can be performed in several ways:

  • Fine needle aspiration, or FNA. Your doctor will use a needle thinner than those used for blood tests. He or she will guide the needle to the area and remove a small amount of the tissue or liquid. Because the needle is so fine, you won't need any local anesthetic. 

  • Core needle biopsy. Your doctor will use a larger needle to remove a cylinder shape of tissue from the area. Usually, several cylinders will be removed. You will likely have a local anesthetic to ease any discomfort.

  • Vacuum-assisted biopsy. Your doctor will first numb the skin and then make a quarter-inch cut and insert a hollow probe. He or she will vacuum up a cylinder of tissue through a hole in the side of the probe while a rotating knife cuts the tissue. Several samples may be taken from the same cut. You won't need stitches.

  • Surgical open biopsy. Under certain circumstances, your doctor may use surgery to remove all or part of an abnormal area. This procedure is usually done under light sedation and with local anesthesia, but it can also be done under general anesthesia, in which you are put to sleep.

Does this test pose any risks?

A biopsy carries a slight chance of infection afterward. Ask your doctor about warning signs to look for, such as fever, pain, or swelling.

What might affect my test results?

Hormone therapy, either for birth control or as hormone replacement, may affect your results.

How do I get ready for this test?

You may need to temporarily stop taking hormone medication. In addition, be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.


Related Items
Wellness Library
  Solving the Breast Cancer Puzzle
  Reducing Your Risk for Breast Cancer
  Certain Factors Help Predict Invasive Breast Cancer
  Hope on the Horizon for Breast Cancer
  Stay Healthy After Breast Cancer
Content Type 167
  CA 15-3
  CA 27-29
Cancer Source
  Sex and Cancer: Questions for Your Doctor
  Breast Cancer—Understanding Genetic Testing
  The Soy and Breast Cancer Controversy: Cause for Concern?
  The 'Chemobrain' Phenomenon in Breast Cancer
  MRIs for Breast Cancer Screening—Who Needs Them?
  Hormonal Therapy: Managing Side Effects in Women
  If You Are Having Hormonal Therapy
  What Is Breast Cancer?
  What to Know About Your Treatment Choices for Breast Cancer
  Ductal Carcinoma
  Statistics About Breast Cancer
  Can I Get Checked for Breast Cancer Before I Have Symptoms?
  What Can I Do if I Am at Risk for Breast Cancer?
  What Are the Symptoms of Breast Cancer?
  How Does My Doctor Know I Have Breast Cancer?
  Tests That Help Evaluate the Traits of Your Breast Cancer
  Understanding Your Grade and Stage of Breast Cancer
  What to Know About Surgery for Breast Cancer
  Breast Cancer: What Happens After Reconstructive Surgery
  Goal of Chemotherapy for Breast Cancer
  Do What You Can to Ease Side Effects of Treatment and Symptoms for Breast Cancer
  Finding Out You Have Breast Cancer
  What to Know About Combination Therapy for Breast Cancer
  How You Get Radiation for Breast Cancer
  What You Need to Know About Hormone Therapy for Breast Cancer
  Tips for Feeling Your Best During Treatment for Breast Cancer
  Taking Care of Your Incision After Breast Surgery
  How Your Doctor Uses Biopsies to Make Your Diagnosis of Breast Cancer
  Understanding Your Type of Breast Cancer
  What to Know About Inflammatory Breast Cancer (IBC)
  Can I Survive Breast Cancer? What Is My Prognosis?
  Am I at Risk for Breast Cancer?
  Myths About What Causes Breast Cancer
  Questions to Ask About Treatment for Breast Cancer
  What to Expect After Surgery for Breast Cancer
  What Happens During Radiation Therapy for Breast Cancer
  What to Expect After Radiation Treatment for Breast Cancer
  What Happens During Chemotherapy for Breast Cancer
  Making the Decision to Have Hormone Therapy for Breast Cancer
  What Happens During Hormone Therapy for Breast Cancer
  Ovarian Ablation as Hormone Therapy for Breast Cancer
  What to Expect After Taking Hormone Therapy Drugs for Breast Cancer
  What to Know About Targeted Therapy for Breast Cancer
  What Happens During Targeted Therapy for Breast Cancer
  Making the Decision to Have Breast Reconstruction After a Mastectomy for Breast Cancer
  When Breast Cancer Spreads to the Bones
  Exercising After Breast Cancer: Moving Toward Health
  Aromatase Inhibitors for Breast Cancer
Cancer FAQs
  Breast Cancer FAQ
NCI Patient Summary
  Breast Cancer Treatment and Pregnancy (PDQ®)
  Breast Cancer Quiz
  Breast Cancer Risk Assessment
Adult Diseases and Conditions
  Breast Cancer Prevention Trial (BCPT)
  Chemotherapy for Breast Cancer Treatment
  About Clinical Trials: Information from the National Cancer Institute
  How Is Breast Cancer Diagnosed?
  General Information About Breast Cancer
  Other Treatments for Breast Cancer
  National Surgical Adjuvant Breast and Bowel Project (NSABP)
  Radiation Therapy for Breast Cancer Treatment
  Risk Factors for Breast Cancer
  Signs and Symptoms of Breast Cancer
  Stages of Breast Cancer
  Study of Tamoxifen and Raloxifene (STAR)
  Breast Cancer Statistics
  About Taxol
  Breast Health: Three-Step Plan for Preventive Care
  Treatments for Breast Cancer
  Hereditary Breast Ovarian Cancer Syndrome (BRCA1/BRCA2)
  Genetics of Breast Cancer
  Breast Cancer Overview
  Should You Consider Preventive Drugs for Breast Cancer?
  Should You Be Tested for the Breast Cancer Gene?
Test and Procedures
  Breast Biopsy