Vaccine Shows Potential Against Early-Stage Breast Cancer

To build on these achievements, researchers are now tying together what they have learned about treating breast cancer and applying it to possible methods of prevention to reduce the total incidence of the disease by targeted immunoediting of crucial pathways responsible for breast cancer development: treatment of early breast cancer using HER-2/neu pulsed dendritic cells (DCs).

Multiple genetic targets have been found that may help combat breast cancer, including BRCA, estrogen receptors, and HER-2/neu, all of which have been known to predict the severity of disease, recurrence, and overall survival. Developing innovative therapies that target these specific genetic variances may be very beneficial in preventing breast cancer for many women.

In this study, researchers investigated a potential vaccine that targets HER-2/neu over-expression in early stage breast cancer, known as ductal carcinomas in situ (DCIS, or early stage cancer formation in the breast's milk ducts). It is estimated that 50-60% of DCIS is directly related to HER-2/neu overexpression.

Patients with HER-2/neu overexpression were given a therapy of DCs (which work with the B- and T-cells to trigger immune responses) that were treated with HER-2/neu to induce an immune response. The participants received four weekly vaccinations into normal lymph nodes in their groins and were evaluated both pre- and post-vaccination for immune response, level of HER-2/neu expression, and cell infiltrates.

The researchers found that most patients responded well to the vaccination. Nearly all patients (11 of 12) demonstrated an initial immune response (shown by the presence of anti-HER-2/neu specific CD4+ T cells), and many of the patients developed protein antibodies to fight the HER-2/neu cells. Patients began to accumulate reserves of white blood cells following treatment and appeared to demonstrate long-term immune responses to HER-2/neu as a result of the therapy. Of the 12 study participants, six showed noticeably decreased levels of HER-2/neu expression after the vaccination, and as a result, the investigators also noted an improvement in the severity of their disease.

"The results demonstrate for the first time that this DC vaccination may have significant clinical activity against certain types of breast cancer,” said Brian J. Czerniecki, M.D., from the University of Pennsylvania (Philadelphia, USA), and lead author of the study. "We are confident that targeted treatment with this vaccine may effectively fight not only DCIS, but may extend to prevention of breast cancer entirely.”

The study was presented November 13, 2006, at the American Association for Cancer Research's Frontiers in Cancer Prevention Research meeting in Boston (MA, USA).