Cancer Vaccine Eliminates Tumors in Early Breast Cancer
Four injections of a new cancer vaccine resulted in the elimination of tumors in nearly 20% of women with a form of early breast cancer called ductal carcinoma in situ (DCIS). Discovery of the cancer vaccine may also help researchers apply their findings to invasive breast cancer and other certain solid tumors.
Cancer vaccine may fight early breast cancer
Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. This form of breast cancer originates in the milk ducts and has not spread beyond that point into normal surrounding breast tissue.
The American Cancer Society reports that about 63,300 new cases of DCIS will be diagnosed this year in the United States, which represents about 20% of new breast cancer cases. Having DCIS increases the risk of developing invasive breast cancer in the future or for having breast cancer come back. The majority of cancer recurrences happen within 5 to 10 years after the initial diagnosis.
The new cancer vaccine findings
A research team at the Perelman School of Medicine and the Abramson Cancer Center at the University of Pennsylvania have found that injecting 27 women who had HER2-positive DCIS with an anti-HER2 dendritic cell vaccine composed partly from each patient’s own cells was capable of eliminating the tumor in nearly 20% of the patients.
HER2-positive breast cancer is a breast cancer that tests positive for human epidermal growth factor receptor 2 (HER2), a protein that promotes the growth of cancer cells. In about 20% of breast cancers, the cancer cells produce an excessive amount of HER2 due to a gene mutation.
The researchers also found that more than 85% of the women seemed to have a sustained immune response after receiving the vaccine series, which may reduce their risk of developing invasive breast cancer down the road.
The vaccine was developed by isolating certain white cells from each woman’s blood and then activating the dendritic cells, which play a key role in the immune system. These cells were then primed with pieces of the HER2/neu protein.
The resulting vaccine was administered to each patient in a series of four shots, one week apart. Two weeks after the last injection, the women underwent surgery to remove any signs of remaining breast cancer.
According to Brian Czerniecki, MD, PhD, surgical director of the Rena Rowan Breast Cancer and surgical director of the Immunotherapy Program for the Abramson Cancer Center, the new cancer vaccine targets the HER2/neu, “which is critical for survival of early breast cancers. If we knock it out with the immune response, we cripple the tumor cells.”
Advantages of the new cancer vaccine
The new vaccine technique has several advantages over testing a vaccine in patients with more advanced breast cancer:
- Patients’ immune systems are still responsive to treatment. In this study, in addition to the 5 patients whose tumors were gone by the time they underwent surgery, 11 patients showed elimination of HER2 expression and 2 others had a 20% or greater reduction in HER2 expression. In fact, some patients maintained an immune response for up to 52 months
- Activated immune cells have fewer tumor cells to attack and kill
- The new vaccine allows clinicians to see results quickly by checking serum and tumor biomarkers
Only low-grade side effects were associated with the new vaccine, including malaise (72% of patients), soreness at the injection site (59%), chills (38%), fever (28%), and headache (24%).