HER2 Negative Vs Positive Breast Cancer

HER2 is a protein that speeds up the growth of breast cancer cells. The concentration of this protein in cancer cells determines whether it is HER2- positive or HER2- negative. In this article, we’ve compared HER2 Negative vs Positive breast cancer.

You’ve undoubtedly heard about HER2 if you’ve been diagnosed with breast cancer or if a loved one has. What it signifies to have HER2-negative or HER2-positive cancer may be something you’re curious about.

In the 1920’s the Human Epidermal Growth factor receptor 2 (HER2) was discovered.

Breast cells have HER2 proteins on their surface. They have a role in healthy cell proliferation but have the potential to become “overexpressed”. This indicates that a person has higher-than-average quantities of protein.

In the 1980s, scientists came to the conclusion that an excess of the HER2 protein might hasten the growth and spread of cancer. This discovery sparked an investigation into methods for reducing or modifying the proliferation of these cancer cells.

How to Diagnose?

In order to find which type of HER2 breast cancer one has, the following tests are performed.

• Immunohistochemistry (IHC) test
• In situ hybridization test (ISH) which can include the FISH (fluorescence in situ hybridization) test

An example of a genetic test is an ISH test. A pathologist really counts the HER2 receptors on the breast cancer cells during an IHC test.

Numerous ISH and IHC tests have received approval from the Food and Drug Administration (FDA). In order to know if you may benefit from specific treatments, a doctor must do a test for HER2 overexpression.

What if you have HER2-positive breast cancer?

HER2 protein levels are unusually high in breast tumors that are HER2-positive.

The cells may multiply more quickly as a result of this. Overproduction can lead to breast cancer that grows quickly and is more prone to spread.

Between 2014 and 2018, 14% of new cases of female breast cancer in the US were HER2-positive patients. [ref]

Significant advancements have been made in HER2-positive breast cancer treatment during the past three decades.

What if you have HER2-negative breast cancer?

HER2-negative breast cancer is defined as having normal amounts of HER2 proteins in its cells.

Your tumor could still be estrogen- or progesterone-positive even if it doesn’t express the HER2 protein. Your options for therapy will also depend on whether it is hormone-positive.

Between 2014 and 2018, 78% of new cases of female breast cancer in the US were HER2-negative instances. The HER2 status was uncertain in 7% of patients. [ref]

How does HER2 positive or negative affect your therapy?

For more than 3 decades, many studies have been conducted in order to find out several possible options to treat HER2 breast cancer.

The prognosis for breast cancer in stages 1, 2, and 3 has now improved thanks to targeted therapy.

Targeted treatments are a common component of care for HER2-positive breast cancer, but they are seldom employed in the treatment of HER2-negative breast cancer.

HER2-negative therapies frequently use oral drugs, which is another distinction between HER2-positive treatments and HER2-negative treatments. Treatments for HER2-positive cancers are often injected or given intravenously (via an IV).

Hormonal therapy may also be suggested for HER2-positive or HER2-negative breast tumors that are estrogen- or progesterone-positive.

How does HER2 positive or negative affect the staging of breast cancer?

HER2 status mainly determines the unique pathophysiology of breast cancer and it also suggests how aggressive cancer can be. Your doctor then assesses the treatment choices.

In 2018, the American Joint Committee on Cancer (AJCC) incorporated HER2 status in the breast cancer staging system. [ref]

A number of additional aspects to be considered while breast cancer staging:

• If aberrant cancer cells appear
• The tumors’ dimensions
• Hormone status of cancer, if it has progressed to neighboring lymph nodes, whether it has gone outside of the breast, and more

In HER2 positive

The tumor size is about 2 to 5 cm and it has spread toward lymph nodes. Also, it is both estrogen and progesterone positive.

In HER2 negative

The tumor size is about 2 to 5 cm and it is hormone-positive and has not spread beyond the breasts.

Treatments for HER2 positive

When combined with chemotherapy, trastuzumab (Herceptin) has improved the prognosis for people with HER2-positive breast cancer. The main therapy for the illness is frequently this specific medication.

A biological treatment that is given intravenously is called trastuzumab (Herceptin).

Trastuzumab, when combined with chemotherapy, reduced the progression of HER2-positive breast cancer more effectively than chemotherapy alone, according to several studies. This combination has given some people long-lasting remissions.

The duration of this medication’s treatment is up to a year. To avoid adverse effects, cardiac monitoring is done for at least 2 years after the therapy is finished

Some other options may include the following.

Margetuximab-cmkb (Margenza):

This is the most recent HER2 medication. Patients with at least two prior HER2 therapies can use it to treat more advanced or metastatic breast cancer.

Pertuzumab (Perjeta):

Pertuzumab (Perjeta) is sometimes used with Herceptin. It is mainly suggested for HER2-positive tumors that have progressed to the lymph nodes, stage 2 tumors, or tumors with a high chance of recurrence

Biosimilars to Herceptin:

Biosimilar dugs are not identical replicas. However, they are reverse-engineered to have comparable effects. Five Herceptin biosimilars, including trastuzumab-dkst (Ogivri) and trastuzumab-qyyp, have received FDA approval.

Neratinib (Nerlynx):

Neratinib (Nerlynx) is advised with Herceptin therapy when there is a greater risk of cancer recurrence

Trastuzumab/hyaluronidase-oysk (Herceptin Hylecta):

Herceptin Hylecta was approved by FDA in 2019. The drug Herceptin Hylecta is injectable. It can thus be administered quicker than Herceptin. Monitoring of the heart is also necessary.

Treatments for HER2 negative

Common medications used to treat hormone-negative, HER2-negative breast tumors include:

• talazoparib (Talzenna)
• sacituzumab govitecan (Trodelvy)

Some other drugs for HER2-negative breast cancer include:

• Alpelisib (Piqray)
• Palbociclib (Ibrance)
• Everolimus (Afinitor)
• Abemaciclib (Verzenio)
• Olaparib (Lynparza)
• Ribociclib (Kisqali)

HER2 Negative Vs Positive Breast Cancer Summarized: