Hormone Receptor and HER2 Status in Breast Cancer Patients

If you have been diagnosed with breast cancer, it is almost decided that the surgeon will ask for a biopsy. During a biopsy, a sample of the cancer-affected tissue is taken for pathological analysis. A biopsy can be conducted before surgery or during surgery for breast cancer removal. The pathological report tells you the hormone receptor status. That is, it tells you whether the cancer cells in your breast possess receptors that are sensitive to the two hormones, estrogen and progesterone.

The receptors are actually proteins present on the surface of the cells that identify the triggers and accordingly signal the cells to grow. In the case of breast cancer, hormone receptors, if present, pick up hormone signals and tell the cells to grow. These receptors are present in normal breast cells and some types of breast cancer cells as well.

Hormone Receptors Are of the Following Two Types:

ER-positive cells: These are the breast cancer cells that have estrogen receptors and are hence called ER-positive. According to WebMD, it is reported in almost 80 percent of all breast cancers.
PR-positive cells: These are the breast cancer cells that have progesterone receptors and are hence called PR-positive. According to WebMD, it is reported in almost 60 percent of all breast cancers.

Breast cancer cells may have just ER-positive or PR-positive cells or both. Apart from hormone receptor status, there is something called HER-2 positive or negative breast cancer. HER2 is actually a protein made by cells in the breast. Nearly 20 percent of the breast cancer cells make this protein, and such a cancer is characterized as fast-growing or aggressive. Such cancers are almost always treated with the help of specific drugs along with chemotherapy after the surgery. This article talks about some of the important things that you must know about the hormone receptor.

Importance of Knowing Hormone Status During Breast Cancer Treatment

Immunohistochemistry (IHC) is the most common test used to check or confirm the presence of receptor cells in the breast cancer tissue retrieved during a biopsy. The most important reason why knowing hormone receptor status is that the cancer treatment plan prepared by the oncologists will depend on the kind of cells that you possess. It helps them make the best treatment decisions, based on the type, extent, spread, and hormone receptor status of your cancer.

A tumor is regarded as hormone-receptor-positive if at least one percent of the cells that are pathologically tested possess estrogen or progesterone receptors. If the concentration is less than one percent, the cells are treated as hormone-receptor-negative. The hormone receptor status of the breast cancer cells clears the picture for the oncologists. For example, hormone-receptor-positive cancer grows slowly, and women with this type of cancer have a better short-term outlook.

On the other hand, hormone-receptor-negative cancers grow quickly and faster than hormone-positive cells and cancer relapse, if it happens, happens in the initial few years after the first treatment. Additionally, ER/PR-positive tumors are more likely to respond to hormone therapy as compared to ER/PR-negative tumors. There are different types of medications and drugs available for hormone therapy. These drugs work by blocking the hormonal receptors or lowering the levels of estrogen in the body. These may include tamoxifen and class of drugs known as aromatase inhibitors and CDK 4/6 inhibitors.

Breast Cancer HER2 Status

HER2, a growth-promoting protein, is present on the surface of all breast cells. However, some breast cancer cells may possess a higher than normal concentration of this protein. Such cancer cells are known as HER2-positive. Such cancers are more likely to spread quickly and aggressively. It is important to know the HER-2 status of cancer in women who have been diagnosed with invasive breast cancer. This is because such cancers are more likely to be benefited from the use of drugs that target the HER2 protein.

A Fluorescent in situ hybridization (FISH) or IHC, conducted at the time of biopsy testing, confirm whether the cancer is HER2-positive or not. In case the result is 0 or 1+, the cancer is regarded as HER2-negative. Such cancers do not respond to drugs that target the HER2 protein. If the result is 3+, the cancer is HER-2 positive and respond well to drugs that target this protein. The HER2 status is not clear and further testing is required if the result is +2.

Triple-negative Versus Triple-positive Breast Cancer

Triple-negative breast cancers do not have too much HER2 protein. Additionally, they do not possess ER and PR hormone receptors. This type of cancer is more common in African-American and Hispanic women, in addition to younger women. Triple-negative breast cancers are more likely to spread quicker than any other type of breast cancer. In addition, treatment is a bit tricky. Because the protein and the hormone receptors are absent, specific drugs cannot be used to target HER2 protein or block ER/PR hormone receptors.

Therefore, such patients are treated with the help of drugs most suitable for chemotherapy. Triple-positive breast cancers have too much of HER2 and also possess ER/PR hormone receptors. The drugs that target HER2 can be used for the treatment of women who have triple-positive breast cancer. Additionally, drugs that block ER/PR hormone receptors can also be used for their treatment.