Breast cancer is the most common type of cancer among women globally. It is said, that about 1 in 8 women will develop breast cancer during their lifetime. The breast cancer receptor status can help understand the most relevant treatment modality.

Breast Cancer Receptor Status

Not surprisingly, it is also a cancer-type that attracts researchers, scientists and doctors around the world to innovate on diagnostic and treatment systems for it. Today, there are several innovative targeted and hormone therapies that exist solely for the purpose of treating breast cancer. Before you start your treatment however, it is important to understand the kind of procedure that will generate the most effective and positive results for you.

What You Should Know

Breast cancer is a diverse disease composed of several biologic subtypes that have distinct behavior. We spoke to several breast cancer experts, and identified two questions that every recently-diagnosed breast cancer patient needs to ask. They are:

  1. What is my Hormone Receptor Status?
  2. What is my HER-2-Neu Receptor Status?

Before we begin to understand those terms, let’s ask a more basic question.

Why Do You Need To Know This?

The answer is simple – you need to know because you want to find the most relevant treatment for your cancer. These receptors activate tumour cell growth on receiving signals from circulating hormones. Knowledge about the overexpression of such receptors on cancer cells can help devise treatment strategies for a patient.

The good news for breast cancer patients is that there are quite a few FDA approved therapies that could be relevant to your condition if you know your receptor status. Shockingly, a survey among recently diagnosed patients demonstrated an extremely limited understanding of hormone and HER2 receptor status .

So, let’s break it down.

What Is A ‘Receptor Status’?

Cancer occurs due to the uncontrolled proliferation, or growth of cells. Receptors are essentially proteins on the cell surface or inside, that can attach to molecules/other substances in the blood that promote cell growth. Knowing whether they are present or not in the cells, can help us understand what is contributing to the growth of cancer cells, and allows us to administer therapies that target those specific receptors to slow down or stop this growth.

So, What Are The Receptor Statuses That You Should Know About?

You need to know about ER, PR and HER2 status. Let’s discuss these one at a time.

Hormone Receptor Status (or ER/PR Status)

What Are Hormone Receptors?

Breast cancer cells have receptors that attach to hormones such as estrogen and progesterone. They are called ER and PR receptors respectively. Every breast cancer patient is unique. Some patients have breast cancer cells that have a higher count of these receptors and some patients have a lower count. Cells that have a higher number of receptors for estrogen are ER-positive, and cells that have receptors for progesterone are PR-positive.

Thankfully, there are very specific therapies available today that help stop tumour growth in patients who have an ER-positive or PR-positive receptor status.

Therapy For ER+ or PR+ Breast Cancer

These cancers can be treated with hormone therapy. Hormone therapy reduces and controls the level of hormones in the cell microenvironment, thereby slowing tumour growth. Tamoxifen is the commonly used ER/PR receptor blocker which prevents tumour cell growth by blocking such receptors. Breast cancer patients who are ER/PR positive, have cancers that tend to grow slow but can come back.

Okay, But I’ve Also Heard About HER-2 Neu Receptor Status. What Is That?

HER-2 stands for Human Epidermal Growth Factor Receptor-2.

The HER-2 gene produces HER-2 receptors, which are essentially a type of protein on the cell surface. Under normal circumstances, these proteins allow for healthy cell growth. But in 15-25% of cases, there is an overproduction of HER-2 genes and therefore, of HER-2 receptor proteins.

This leads to the uncontrolled growth of breast cancer cells owing to excessive stimulation of growth by overexpression of HER2 receptors.

So… Is That A Bad Thing?

Not knowing about HER2 status is a bad thing since overexpression of HER2 receptors has been found to be associated with higher rates of recurrence, distant spread and resultant death. So it is recommended to test for HER2 status for every patient with breast cancer.

Thankfully, we now have specific HER-2 targeted therapies that reduce recurrence and metastasis and are easily available. Among the more commonly prescribed medications, are Herceptin (trastuzumab), Kadcyla (trastuzumab emtansine), Nerlynx (neratinib), Perjeta (pertuzumab) and Tykerb (lapatinib).

For drugs like trastuzumab, even biosimilars (generics that are slightly cheaper) are widely available now. So check with your doctor on what therapy is the most relevant for you.

This Is Great! So How Do I Find My HER-2 Receptor Status? Your doctor can prescribe an IHC or FISH test to determine your receptor status.

IHC Test

IHC stands for Immuno-Histo-Chemistry. The results of an IHC test can be: 0 (negative), 1+ (also negative), 2+ (borderline), or 3+ (positive — HER2 protein overexpression).

0 or +1 indicates: HER-2 Negative
+3 indicates: HER-2 Positive
+2 indicates: Borderline, or ‘Equivocal’ results. In such cases, a FISH test is needed to determine the status.

FISH test (Fluorescence In Situ Hybridization):

The Fluorescence In Situ Hybridization test finds out if there are too many copies of the HER-2 gene in the cancer cells. The results of the FISH test can be positive (HER-2 gene amplification) or negative (no HER-2 gene amplification).

What Is ‘Triple Negative Breast Cancer’?

Triple negative breast cancers don’t have ER or PR receptors and they don’t generate much HER-2 protein either which means that their growth is not dependent on receptor stimulation and there are no targeted therapies (like those for HER2 positive cancers) available for these cancers.

They are more commonly seen in younger women, and are aggressive in nature. Currently, Chemotherapy is the only treatment modality available for such patients, and patients with triple negative breast cancer are at higher risk of recurrence and metastasis.

I Don’t Have Breast Cancer. Do I Still Need To Get Screened For These Receptors?

No. The receptor tests are recommended only for patients having invasive breast cancer.

With each passing minute, the oncological community is discovering better ways of diagnosing and treating cancer. So, accurate knowledge about your disease and access to correct treatment protocols is essential to achieve positive long term results.