What defines HER2-positive breast cancer?

HER2-positive breast cancer is characterized by elevated levels of the HER2 protein, which is a growth factor that promotes the growth of cancer cells. In normal breast cells, HER2 is present at low levels, but in HER2-positive breast cancers, there is an abnormal overexpression of this protein. This overexpression is a key feature that helps in diagnosing this subtype of breast cancer and influences treatment decisions, as HER2-positive cancers are often more aggressive and may require targeted therapies like trastuzumab (Herceptin).

The presence of elevated HER2 levels makes it possible to identify specific treatment strategies that can more effectively target the cancer, thereby improving the outcomes for patients with this subtype. Understanding the role of HER2 is critical for both prognosis and management, as it allows for personalized treatment approaches tailored to the unique biological characteristics of the cancer.