As much as I love new vaccine technology, I also hate getting too excited about studies that take place in mice, especially when you consider that only one out of 250 mice studies go on to produce a useful drug or vaccine for human use. But, I think the new first-of-its-kind preventive vaccine against breast cancer is going to prove to be an exception to the rule. This groundbreaking vaccine has mostly slipped below the media radar, even as the results (a study at Cleveland Clinic just published in Nature Medicine) were so remarkable that human trials are about to begin.

Each year in the US, more than 190,000 women are diagnosed with breast cancer. Most breast cancers produce alpha lactalbumin, a milk protein, which is only produced at one other time, when a woman is breast feeding.The new vaccine targets this protein, and in the study it was 100% successful at preventing breast cancer in highly susceptible mice who otherwise developed breast cancer 100% of the time.

The vaccine caused a very strong T cell immunological reaction against the alpha lactalbumin that the tiniest tumors began to make, destroying these tumors before they could grow. The vaccine was well tolerated with few side effects, and we would have the same expectation in humans, as long as they aren’t lactating.

This vaccine is revolutionary, the first of its kind, a real preventive vaccine—it holds significant promise for women beyond their child-bearing years when the risk of breast cancer is very high.

Marc Siegel, MD, is an internist and professor of medicine at New York University and the author of False Alarm: The Truth About the Epidemic of Fear