Immunohistochemical Test for Estrogen and Progesterone Receptors
Does this test have other names?
ER/PR IHC testing
What is this test?
This test looks for several types of receptors on cells in a sample of breast cancer
Fifty percent to 70% 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
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% 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 healthcare 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 provider sends the tissue sample to a lab. There, a pathologist runs
tests on the tissue sample and looks at the cells under a microscope.
Why do I need this test?
You may need this test if you have breast cancer and your healthcare provider 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 trastuzumab, pertuzumab, or lapatinib.
What other tests might I have along with this test?
Your healthcare provider 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
Genetic testing of the tumor sample. This test, also called Oncotype DX, will help your healthcare provider decide whether
you need chemotherapy.
Lymph node needle biopsy. It's common for breast cancer to spread to nearby lymph nodes. If your healthcare
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
provider figure out or refine your treatment plan.
What do my test results mean?
Test results may vary depending on your age, gender, health history, the method used
for the test, and other things. Your test results may not mean you have a problem.
Ask your healthcare provider what your test results mean for you.
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 healthcare provider will review your results together to figure out the best
therapy for you. It could be hormone therapy, chemotherapy, or other medicines that
How is this test done?
This test needs 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 done in several ways:
Fine needle aspiration, or FNA. Your healthcare provider 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 healthcare provider will use a larger needle to remove a cylinder shape of tissue
from the area. Usually several samples will be removed. You will likely have a local
anesthetic to ease any discomfort.
Vacuum-assisted biopsy. Your healthcare provider will first numb the skin. He or she will 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 healthcare provider 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 so you will
sleep through the procedure.
Does this test pose any risks?
A biopsy carries a slight chance of infection afterward. Ask your healthcare provider
about warning signs to look for, such as fever, pain, or swelling.
What might affect my test results?
Hormone therapy 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 medicine. Be sure your healthcare
provider 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