Yes, it's in the early stages of research. And yes, it's been tested only on mice. But the procedure developed by Vincent Tuohy and his team, billed as a preliminary breast cancer vaccine, has raised hopes once more that one day in the not-too-distant future such a procedure could be available for humans. In a study this month in Nature Medicine, Tuohy tested the vaccine on mice genetically engineered to be more cancer-prone. The ones that received the full vaccine, with a protein called a-lactalbumin, didn't develop breast cancer. All the others did.