 This study assessed the effect of prophylactic co-immunisation with multi-epitope DNA and peptid cancer vaccines on the 4-T1 breast cancer animal model. The results showed that co-immunisation significantly increased serum levels of IgG1 and IgG2a, enhanced Illinois IV and IFN production, in splenocytes, and improved lymphocyte proliferation rate and Granzyme B production. Additionally, the co-immunised mice exhibited decreased breast tumor volume, 78%, and increased survival time, 37.5%, indicating that prophylactic co-immunisation with these vaccines can activate the immune system against breast cancer. However, further experiments are needed to evaluate their efficacy from different angles. This article was authored by Ashkan Safavi, Amir Hussain Kefiat, Elham Madhava, and others.