Researchers from the University of Georgia (UGA) and the Mayo Clinic in Arizona have developed a vaccine that dramatically reduces tumors in a mouse model, according to a study published online Monday in the journal Proceedings of the National Academy of Sciences. The vaccine works by training the immune system to attack tumors that have a protein known as MUC1 on the surface of their cells. MUC1 is found on more than 70 percent of all cancers that kill. Many cancers, such as breast, pancreatic, ovarian and multiple myeloma, express MUC1 with the shorter carbohydrate in more than 90 percent of cases. \"This vaccine elicits a very strong immune response,\" said study co-senior author Geert-Jan Boons, professor of chemistry at UGA Cancer Center. \"It activates all three components of the immune system to reduce tumor size by an average of 80 percent.\" The researchers are testing the vaccine\'s effectiveness against human cancer cells in culture and are planning to assess its toxicity. If all goes well, they anticipate that phase I clinical trials to test the safety of the vaccine could begin by late 2013.