Interested in sharing your ESR1-mutated, mBC story? Visit or call [888-259-1218] to learn more.

In ER+/HER2- advanced or metastatic breast cancer


Not actual patients.
Not actual patients.

Could this be you?

Nearly 1 out of 2 people with ER+/HER2- metastatic breast cancer may develop an ESR1 mutation after progression on hormone therapy.
I know my cancer’s ESR1 mutation status. You should too.

Not an actual patient.
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1. Ask about status

I learned that ESR1  mutations can be common after treatment like mine.

So, before starting my next treatment, I asked my oncologist about the ESR1  mutation status of my cancer.

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2. Get tested

We did a blood test.

And it showed that my cancer had developed an ESR1  mutation.

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3. Discuss options

Now I know my cancer has an ESR1  mutation.

So, I’m discussing treatment options specifically for my type of cancer with my healthcare team.

I’m a third-grade teacher who is very active. And I’m also a person living with ER+/HER2- metastatic breast cancer.

Like many people with my type of cancer, I was taking hormone therapy and a type of treatment called a CDK4/6 inhibitor. After a little over a year, my disease had progressed, so my healthcare team told me it was time to try a different treatment.

Could your experience be similar to mine? If so, here is more information you may find helpful.

CDK, cyclin-dependent kinase; ER+, estrogen receptor-positive; ESR1, estrogen receptor 1; HER2-, human epidermal growth factor receptor 2-negative.

90% Of People

In ER+/HER2- advanced or metastatic breast cancer, the first treatment for most people is a hormone therapy taken alone or in combination with a CDK4/6 inhibitor.

Hormone therapies
CDK4/6 inhibitors

Ibrance® (palbociclib)
Kisqali® (ribociclib)
Verzenio® (abemaciclib)

But cancer tries to get around treatments by mutating. This may be why the cancer may progress. An ESR1 mutation is an example of a mutation in metastatic breast cancer that may cause treatment to stop working.

Talk with your healthcare team about your cancer’s ESR1  mutation status before starting your next treatment

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Ibrance is a registered trademark of Pfizer Inc. Kisqali is a registered trademark of Novartis AG. Verzenio is a registered trademark owned or licensed by Eli Lilly and Company, its subsidiaries or affiliates.

My healthcare team told me that an ESR1  mutation can impact what treatment may be most appropriate for me.
Not an actual patient.
My healthcare team told me that an ESR1  mutation can impact what treatment may be most appropriate for me.

ESR1  mutations may:

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Develop after taking certain hormone therapies

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Cause your cancer to spread faster

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Make metastatic breast cancer more difficult to treat

Not an actual patient.

I had a blood test to see if my cancer has an ESR1 mutation, which could be the reason my cancer progressed on my current treatment. Ask your healthcare team if you should have a blood test, too.

ESR1  mutations can impact your physician's choice of treatment. So, it’s important to know your cancer’s ESR1  mutation status before starting your next treatment. Blood test results will help you and your healthcare team decide which treatment options are most appropriate for you.

Not an actual patient.

Learn more about being the ESR1 out of 2

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