Stanford University scientists have just made a potentially major discovery with regards to a cancer vaccine after finding a way to use pluripotent stem cells to immunize lab mice against multiple different types of cancers, the university said in a statement. Injecting mice with inactivated induced pluripotent stem cells, or iPSCs, resulted in an immune response that fought back against breast, lung, and skin cancers.

The findings, published in the journal Cell Stem Cell, involved 75 mice that received versions of the iPSC vaccine. Within just four weeks, more than two thirds of vaccinated mice rejected breast cancer cells, and even the 30 percent that still got the tumors had significantly smaller tumors than they would have otherwise had. The results were repeated with lung and skin cancers.

Cancer vaccines must introduce one or more antigens into the body to be effective, and one of the big challenges is the limited number of antigens. In this study, the vaccine was successful in targeting multiple tumor antigens, which got around that problem.

“We’ve learned that iPS cells are very similar on their surface to tumor cells,” said Joseph Wu, MD, PhD, director of Stanford’s Cardiovascular Institute and professor of cardiovascular medicine and of radiology. “When we immunized an animal with genetically matching iPS cells, the immune system could be primed to reject the development of tumors in the future. Pending replication in humans, our findings indicate these cells may one day serve as a true patient-specific cancer vaccine.”