Cancer vaccines and acquired immunity therapy targeting HER2 have been considered as leading strategies for HER2-positive breast cancer treatment.156 Strategies of cancer vaccines designed to produce specific anti-HER2 immunity are under research, including HER2 peptide-based vaccines, plasmid DNA-based vaccines, and vaccines with HER2 delivering in a viral vector.157 Active anti-HER2 immunization could facilitate the ex vivo expansion of HER2-specific T cells in adoptive immunotherapy for the treatment of MBC. This evidence concerns the gene ERBB2 and breast cancer.