Ask the Experts: What is biomarker testing?

Biomarker testing helps us find out what makes a particular breast cancer "tick" -- and helps us find the right treatment.

Transcript

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My doctor mentioned biomarker testing. What does that mean, and why is that important?

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[MUSIC PLAYING] MARYAM LUSTBERG: Thank you for your question. Biomarker testing is simply testing your tumor cells

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to understand what makes them tick, what makes them grow. Our three key biomarkers that help

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us define what type of breast cancer you have are estrogen receptor.

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A receptor is simply a fancy way of saying that these are places on the tumor where the estrogen hormone, which is the predominant female hormone,

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fits. And once it fits into this receptor, it activates the tumor cell. Similarly, we have progesterone receptors.

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Same idea. Progesterone is a common female hormone, and it fits into these receptors, activating the tumor cell.

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Then the third key biomarker is HER2. And I like to explain HER2 as a growth antenna

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that's normally present at low levels in all of our cells. But tumor cells that are very HER2-positive

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have extra growth antennas that they tend to grow more rapidly. But the good news is having extra HER2 also opens up

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a whole range of very specific HER2-directed therapies that are quite effective. So knowing these three biomarkers truly helps you

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and your oncologist know which path to focus on in terms of systemic therapy. [AUDIO LOGO]