Weighing In on the Early Clinical Trials for Breast Cancer Vaccine

PJ Hamel Health Guide
  • Breast Cancer News Headline Timeline: The Search for a Breast Cancer Vaccine
    Research to develop a breast cancer vaccine has been in the news for years. Just take a look at the sampling of Web headlines above. The latest buzzworthy step forward in breast cancer vaccine research was presented recently at the American Association for Cancer Research meeting.
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    The study was conducted in modified mice that have the cancer-producing gene HER-2/neu. After these mice began to develop tumors, they were given the experimental breast cancer vaccine.

    After vaccination, the early development of tumors was either slowed or stopped in all of the mice tested. The strength of the resulting "powerful immune system response to tumor cells," as reported in HealthDay, is what all the buzz is about.

    The basic idea behind some of the early candidates for a breast cancer vaccine is that our immune systems have a hard time identifying cancerous cells. If our immune systems knew how to find those rogue cells, then they could destroy them. So, the hypothetical vaccines offer an array of ways to tag or identify the pesky cancer cells, usually with a modified protein.

    Let's review how this cancer vaccine works, and why is it producing more positive results than earlier models. Without doing TOO deep a dive, current breast cancer vaccines stimulate your body’s T cells to recognize cancer cells as foreign; the T cells respond by calling in your body’s fighting white cells to kill the cancer. Think of T cells as the woman who comes upon a car accident and calls the police on her cell phone; there’s not much she can do at the scene, so she flags down authorities to come to the rescue.

    This T cell-response alone isn’t enough to trigger a strong enough white-cell response. But, the clever researchers have managed to add a certain substance to the vaccine to fool the white cells into thinking cancer is bacteria-–and bacteria gets white cells riled up quickly.

    In addition, when it became apparent that T cells were actually trying to prevent the vaccine from getting into the body, the researchers found a way to neutralize that response enough to allow the vaccine in, while still keeping the T cells active.

    So OK, this is difficult to understand. Suffice it to say, progress is being made; up till now, patients receiving vaccines in clinical trials had to keep re-taking them, usually once a month indefinitely. This new vaccine remained effective for longer, up to 39 weeks, in mice. It's not clear if the improved duration of effectiveness will be consistent in people, but it's something to look forward to, if that's the case.

  • A breast cancer vaccine, if developed, will eventually be used for women with a strong genetic tendency towards breast cancer; for women who’ve already had cancer, as a recurrence preventive; and for women who haven’t responded to traditional treatments. So it could affect a lot of us; here’s hoping an effective breast cancer vaccine gets through the clinical trials and into production.
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    Perhaps most interesting, though, is the difficult path researchers have taken to get to this point: a path that ran directly through New Orleans and Hurricane Katrina. Pilar Nava-Parada, M.D., and Esteban Celis, M.D., were lab-mates at the Mayo Clinic in Rochester, Minnesota, when they started work on this vaccine. In November 2004, they decided to transfer their research to Louisiana State University and Tulane University–-in New Orleans. Bad timing. On August 23, 2005, Hurricane Katrina hit New Orleans, and the colony of mice on which Nava-Parada and Celis had been testing their vaccine, as well as all their data, were lost.

    What to do? Nava-Parada decided to head back to the Mayo Clinic. And now, nearly two years later, her research is on track again, and yielding results. It’s an ill wind that blows nobody any good… Even if that wind is hurricane-force.
Published On: June 13, 2007