- Question from Patty: Any new updates on ER/PR/HER2-negative breast cancer?
Ruth Oratz, M.D., F.A.C.P.
We now are thinking about breast cancer as not just a single disease but as several different subsets, or several different categories of breast cancer based on the biology that is on the molecular characteristics of the tumor cell. These molecular characteristics that we're interested in are the ones that determine the behavior of the cancer cells; for instance, the likelihood that the cancer cells could spread away from the primary site. We are interested in the molecular characteristics that control the growth, the proliferation, and the invasive potential of the tumor cells. The estrogen receptor (ER) and progesterone receptor (PR) are molecular markers that tell us that the cancer cells can respond to hormonal signals, particularly from estrogen. The presence of ER and PR on the cancer cells allows us to use hormonal therapies in order to manipulate, or change, the signal to the cancer cells. In simple terms, we can target those receptors ER and PR with hormonal medication. It is quite effective in preventing the spread or recurrence of breast cancer.
Another molecular marker that we can measure (and there are many) is the HER2/neu receptor. When HER2/neu is present in large amounts on the cancer cells, it confers a more aggressive biologic behavior on the tumor cell. We have very effective targeted therapy against HER2/neu, and the name of that treatment is Herceptin (chemical name: trastuzumab). Herceptin is a biologic treatment, not a chemotherapy drug; rather an antibody that blocks the HER2/neu receptor on the cancer cells. And Herceptin shuts down the signal from HER2/neu. In the so-called triple-negative breast cancer, we do not have ER, PR, or HER2/neu as biologic targets. Therefore, we cannot use hormonal therapy or Herceptin in treating this form of breast cancer. At the present time the standard therapy for triple negative breast cancer is chemotherapy. However, there is a great deal of research on this particular subset of breast cancer to identify other biologic targets for which new treatments will be more effective. There is some indication that using drugs like Avastin (chemical name: bevacizumab) might be beneficial for triple negative breast cancer, and a number of new agents are being investigated both in the laboratory and in clinical trials. I would encourage any patient who has this form of breast cancer to pursue participation in clinical trials.
On Wednesday, September 20, 2006, our Ask-the-Expert Online Conference was called Open for Your Questions. Ruth Oratz, M.D., F.A.C.P. and moderator Beth Baughman DuPree, M.D., F.A.C.S. answered your questions covering a wide variety of issues relating to breast cancer.
The materials presented in these conferences do not necessarily reflect the views of Breastcancer.org. A qualified healthcare professional should be consulted before using any therapeutic product or regimen discussed. All readers should verify all information and data before employing any therapies described here.
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