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HER2 and predicting response to therapy in breast cancer

Hideko Yamauchi, MD
Daniel F Hayes, MD
Section Editor
Harold Burstein, MD, PhD
Deputy Editor
Sadhna R Vora, MD


Breast cancer is a heterogeneous, phenotypically diverse disease composed of several biologic subtypes that have distinct behavior. Amplification or overexpression of the human epidermal growth factor receptor 2 (HER2) oncogene is present in approximately 15 percent of primary invasive breast cancers [1]. Women with both early-stage and metastatic breast cancer that meet criteria for HER2 positivity are treated with regimens including HER2-directed therapy.

Here we will review the definition of HER2 positivity, and the approach to HER2 discordance. Management of those with HER2-positive disease in the neoadjuvant, adjuvant, and metastatic settings, as well as treatment protocols for HER2-positive breast cancer, are discussed elsewhere:

(See "Neoadjuvant therapy for patients with HER2-positive breast cancer".)

(See "Adjuvant systemic therapy for HER2-positive breast cancer".)

(See "Systemic treatment for HER2-positive metastatic breast cancer".)

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Literature review current through: Nov 2017. | This topic last updated: Jun 30, 2017.
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