A cancer vaccine consisting of one or more long, synthetic peptides derived from patient-specific breast cancer tumor-associated antigens (TAAs), with potential immunomodulating and antineoplastic activities. Upon intramuscular administration of the personalized synthetic long peptide breast cancer vaccine, the peptides stimulate the host immune system to mount a cytotoxic T-lymphocyte (CTL) response against tumor cells expressing the TAAs, which results in tumor cell lysis.