Hormone receptor status
Hormone receptor status is a main factor in planning breast cancer treatment. Some breast cancer cells grow with the help of estrogen and/or progesterone (female hormones produced in the body). These cancer cells have special proteins inside, called hormone receptors. When hormones attach to hormone receptors, the cancer cells with these receptors grow.
A pathologist determines the hormone receptor status by testing the tumor tissue removed during a biopsy.
- Hormone receptor-positive (or estrogen/progesterone receptor-positive) breast cancers have many hormone receptors
- Hormone receptor-negative (or estrogen/progesterone receptor-negative) breast cancers have few or no hormone receptors
Hormone receptor status and hormone therapy
Hormone receptor-positive breast cancers can be treated with hormone therapies. These include tamoxifen and the aromatase inhibitors, anastrozole (Arimidex), letrozole (Femara) or exemestane (Aromasin).
Hormone receptor-negative breast cancers are not treated with hormone therapies because they do not have hormone receptors.
Estrogen receptor status and progesterone receptor status
Breast cancers that are estrogen receptor-positive also tend to be progesterone receptor-positive. And, cancers that are estrogen receptor-negative tend to be progesterone receptor-negative.
Sometimes, a breast cancer is positive for estrogen receptors, but negative for progesterone receptors. Because current hormone therapies are designed to treat estrogen receptor-positive cancers, these cases are treated the same as breast cancers that are positive for both hormone receptors.
How do hormone therapies work?
Hormone therapies can stop tumor growth (in hormone receptor-positive cancers) by preventing the cancer cells from getting the estrogen they need to grow. They can do this in different ways. Some hormone therapies, like the drug tamoxifen, attach to hormone receptors inside the cancer cells and block estrogen from attaching to the receptors. Other therapies, like aromatase inhibitors, lower the level of estrogen in the body so the cancer cells cannot get the estrogen they need.
Hormone receptor status and prognosis
Hormone receptor status is also related to the chance of recurrence (the return of cancer after treatment). Hormone receptor-positive tumors have a slightly lower chance of recurrence than hormone receptor-negative tumors in the first five years after diagnosis. However, after five years, this difference begins to decrease and over time, goes away [6,28].
Learn more about hormone therapies.
Learn about hormone receptor status information on a pathology report.
HER2/neu (erbB2) status
HER2/neu (human epidermal growth factor receptor 2), also called ErbB2, is a protein that appears on the surface of some breast cancer cells. This protein is an important part of the pathway for cell growth and survival.
- HER2/neu-positive breast cancers have a lot of HER2/neu protein
- HER2/neu-negative breast cancers have little or no HER2/neu protein
About 15 to 20 percent of all breast cancers are HER2/neu-positive (you also may hear the term “HER2/neu over-expression”) [29-30]. HER2/neu status helps guide treatment.
HER2/neu-positive cancers and trastuzumab therapy
HER2/neu-positive breast cancers can benefit from the drug trastuzumab (Herceptin), which directly targets the HER2/neu receptor . Trastuzumab is not used for HER2/neu-negative cancers.
Learn more about trastuzumab (Herceptin).
Learn about emerging targeted therapies for HER2/neu-positive metastatic breast cancer.
Testing for HER2/neu status
All tumors should be tested for HER2/neu status. There are two common ways to determine HER2/neu status are:
- Immunohistochemistry (IHC) testing detects the number of HER2/neu protein receptors in the cancer calls
- Fluorescence in situ hybridization (FISH) testing detects the number of HER2/neu genes in the cancer cells
Learn about HER2/neu status information on a pathology report.
How fast a tumor grows (known as its proliferation rate) can help show how aggressive a tumor is and how likely it is to spread to other parts of the body. Tumors with a high proliferation rate (those that are growing fast) often have a poorer prognosis than those with a low proliferation rate.
Proliferation rate is an important predictor of prognosis and whether or not a tumor will respond to chemotherapy. However, there are issues related to its measurement, so while some health care providers may use it to help guide treatment options, others do not.
The Ki-67 test is a common way to measure proliferation rate. When cells are growing and dividing (proliferating), they make proteins called proliferation antigens. By counting the number of cells with these antigens, a pathologist can determine a tumor's proliferation rate.
The antibody to Ki-67 attaches itself to the proliferation antigen. The more cells the Ki-67 antibody attaches to on a tissue sample, the more likely the tumor cells are to grow and divide rapidly. The result of this test is reported as the percentage of Ki-67-positive cells. It shows whether a low, moderate or high proportion of cancer cells are in the process of dividing.
Learn about proliferation rate information on a pathology report.