DNA vaccine developed at the Karmanos Cancer Institute fights HER2-positive cancers

Researchers at the Barbara Ann Karmanos Cancer Institute and Wayne State University School of Medicine have developed a HER2 DNA vaccine that has shown to be effective on drug resistant tumors in mice. The study was reported in the September 15 issue of Cancer Research, a journal of the American Association for Cancer Research.

Wei-Zen Wei, Ph.D., professor at the Barbara Ann Karmanos Cancer Institute and Department of Immunology and Microbiology, Wayne State University School of Medicine, together with a team of researchers have been working on a series of cancer-fighting vaccines since 1996 to help prevent HER2-positive breast cancer.

Approximately 20 - 30 percent of breast cancers make too much of the protein called HER2, which is made at low levels by normal breast cells. Tumors that overexpress HER2 (called HER2-positive) tend to grow faster and are more likely to come back than tumors that don't overexpress the protein.

According to Dr. Wei, this HER2 DNA vaccine was tested in the laboratory on tumor cells that no longer responded to other therapies for HER2-positive breast cancer. The results in mice showed that the vaccine prevented the cancer from growing and was not toxic.

"We each have an immune system to help fight off disease," explained Dr. Wei. "However, when cancer develops, the immune system can't always distinguish tumor cells from normal cells, so the full power of the immune system is not harnessed to fight the disease. This vaccine helps to educate the immune system so that it recognizes HER2-positive cancer cells, helps destroy them and prevents them from spreading."

Dr. Wei's lab is the first to develop HER2 DNA vaccines. The first vaccine was developed in 1999. In collaboration with the Karolinska Institute in Stockholm, Sweden, a pilot clinical trial with the HER2 DNA vaccine has been conducted in patients with Stage IV breast cancer and has demonstrated safety. Further testing is being considered.

Dr. Wei added, "As we continue our extensive research on this promising vaccine, based on the results to-date, we believe this could eventually help control the spread of HER2-positive breast cancer in patients who have been resistant to other treatments, and possibly prevent HER2-positive breast cancer from occurring."

Other researchers working with Dr. Wei include: Paula J. Whittington, Marie P. Piechocki, Henry H. Heng, Jennifer B. Jacob, Richard F. Jones and Jessica B. Back.