"A vaccine to prevent breast cancers return in women with a history of the disease has triggered the desired immune response in early research.    The vaccine under development is aimed at preventing recurrence in women who have a form of tumor known as HERpositive according to researcher Dr. Diane Hale a research resident in general surgery at Brooke Army Medical Center at Fort Sam Houston in San Antonio.    She is set to present results of the study on Monday at the annual meeting of the American Association for Cancer Research in Chicago.    The vaccine known as the HERbased peptide vaccine AE is designed to harness the power of the patients immune system based on its reaction to a cancerlinked peptide protein.    The theory is that once you form that immune response to the specific peptide if the body has a recurrence it will recognize that cancer as a bad thing a foreign thing Hale explained in an association news release.    The study is a phase  study meant to evaluate the vaccines effectiveness and any side effects. Phase  studies are needed before the vaccine could be approved.    The science is early Hale stressed and it will take at least five years before the vaccine could conceivably be available if ongoing studies bear out.    HERpositive breast cancer tests positive for a protein known as human epidermal growth factor receptor  or HER which promotes the tumor cell growth. About one of every five breast cancers involves cancer cells that churn out an excess of HER due to a genetic mutation. HERpositive breast cancers are often more aggressive than other types according to the American Cancer Society.    The goal of the vaccine Hale said is to educate the body to respond to that HERbased peptide so it will recognize the cancer when it recurs and attack it.    If your immune system has been educated by the vaccine to recognize the tumor cells we think it will allow the immune system to take care of any individual cancer cells trying to set up shop explained Dr. Elizabeth Mittendorf a surgical oncologist at the University of Texas M.D. Anderson Cancer Center in Houston. She is the principal investigator on the trial.    The study involved  breast cancer survivors who had gone through their treatment and were free of disease at the start of the trial. The women were randomly assigned to receive either the vaccine paired with an immune stimulant or the immune stimulant alone.    The women received monthly injections for six months. The researchers then conducted a variety of tests to gauge each womans immune system response.    The investigators found that in the vaccinated group  percent of patients showed a significant response compared with  percent of those in the control group who did not get the injection.    How to explain the  percent who responded without the vaccine For the controls even without having their immune systems educated towards HER specifically they may still mount a response because they have previously seen HER within their own cancer Hale said.    Those who were vaccinated also displayed a decrease in certain cells that suppress the immune system. That is a good thing Hale said because an increase in these cells has been found to be associated with cancer recurrence.    Don Diamond director of translational vaccine research and a professor of virology at the City of Hope Comprehensive Cancer Center in Duarte Calif. reviewed the findings and said Their approach is well thought out and makes sense.    Still the study remains very preliminary he cautioned. Whether it actually has an increase in survival remains to be seen he said.    That study will be done Hale said and they plan to follow the women for three years and look at survival differences.    But until the vaccine is linked to an actual survival benefit or improvement in tumor status Diamond said no one can say if it helps the patients in a meaningful way.    Numerous vaccines to prevent breast cancer recurrence are currently under study he noted.    Findings presented at medical meetings are typically considered preliminary until published in a peerreviewed journal.     More information  To learn more about immunebased cancer therapies visit the American Cancer Society.  SOURCES Diane Hale M.D. research resident in general surgery Brooke Army Medical Center Fort Sam Houston San Antonio Don Diamond Ph.D. director translational vaccine research and professor virology City of Hope Comprehensive Cancer Center Duarte Calif. Elizabeth Mittendorf M.D. surgical oncologist University of Texas M.D. Anderson Cancer Center Houston presentation April   annual meeting American Association for Cancer Research Chicago"