Lastly, researchers in the United states have developed a vaccine that delays and prevents breast tumors in mice. This vaccine involves the injection of telomerase peptide, an antigen found in 90% of breast tumors, to stimulate an immune response to the tumor. Thus far, the vaccine prevented tumors in mice with the HER2/neu breast cancer gene and slowed in development of tumors in mice without the HER2/neu gene (Science Daily,2007).