- Question from Joan: Was there anything new presented regarding triple-negative breast cancer?
Ruth Oratz, M.D., F.A.C.P.
Yes, triple-negative breast cancer is a subset of breast cancer that is of great concern clinically. This subset of breast cancer means that the tumor cells are negative: they don't express the estrogen receptor, the progesterone receptor, or the HER2/neu receptor. They're negative for all three of these biologic markers, which can serve as targets for therapy. The implication of this is that the mainstay of treatment for triple-negative breast cancer is chemotherapy. There is a tremendous clinical need for better understanding of the biological processes that drive the growth and proliferation of triple-negative breast cancer cells. Two very interesting abstracts were presented at the meeting in San Antonio about possible molecular pathways, which may play an important role in the biology of triple-negative breast cancer. One of these described the higher expression of a gene called GRB7. Higher expression of GRB7 was associated with an increased risk of recurrence and did not correlate with any other clinical characteristics of either the tumor or the patient, except that lower expression of GRB7 was often present in women who were older than age 65. GRB7 played a critical role in signaling the molecular pathways which affect motility, migration, adhesions, and interaction between the tumor cells and its surrounding tissue. All of these factors are related to the ability of the malignant cancer cells to metastasize, and in particular to triple-negative breast cancer cells. GRB7 may present a new promising target for treatment for triple-negative breast cancer. Another interesting abstract related to triple-negative breast cancer was the presentation about a new drug called dasatinib. This is a powerful oral drug which seems to inhibit some of the pathways related to metastatic activity of triple-negative cells, perhaps including those that have to do with GRB7. In one small clinical trial, which was a Phase II study of dasatinib in 36 patients with advanced triple-negative breast cancer who had received prior chemotherapy, four patients had meaningful clinical responses, and another four patients showed some transient benefits from treatment. Although this was a small study, and activity was modest in this trial, dasatinib may be a promising agent and it deserves further study in less heavily pre-treated patients with triple-negative breast cancer. Dasatinib is a targeted biologic agent and may be more effective if given in combination with chemotherapy. Additional research will be looking at these questions.
The Ask-the-Expert Online Conference called Updates From the 2008 San Antonio Breast Cancer Symposium featured Ruth Oratz, M.D., F.A.C.P. and Carol Kaplan, M.D. answering your questions about the latest updates on breast cancer risk, screening techniques, treatment options, and more.
Editor's Note: This conference took place in December 2008.
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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