HER2-positive breast cancer

You're probably referring to HER2-positive breast cancer — a breast cancer that tests positive for a protein called human epidermal growth factor receptor-2 (HER2), which promotes the growth of cancer cells. In about one of every three breast cancers, the cancer cells make an excess of HER2 due to a gene mutation. This gene mutation can occur in many types of cancer — not only breast cancer.

HER2-positive breast cancers tend to be more aggressive than other types of breast cancer. They're also less responsive to hormone treatment. However, two treatments that may be effective against HER2-positive breast cancer are:

• Trastuzumab (Herceptin) — a drug that targets HER2 — may slow the growth of the cancer and even decrease its size. Herceptin may be used as a treatment by itself or combined with chemotherapy. A study published in 2005 also found that Herceptin can reduce breast cancer recurrence by as much as 50 percent.
• Certain chemotherapy medications, such as combinations of anthracycline drugs (doxorubicin, epirubicin).

Breast tissue can be tested for HER2, and routine testing is recommended for most women with breast cancer because the results may affect treatment recommendations and decisions. Whenever breast cancer recurs or spreads, the cancer cells should be tested for HER2.