An off-the-shelf (OTS), microbiome therapeutic cancer peptide vaccine composed of two onco-mimics, which are immunogenic microbiomal-derived peptides that are highly homologous to specific tumor-associated antigens (TAAs) and are obtained and selected from the human gut microbiome, combined with the helper peptide and CD4-positive T-cell epitope universal cancer peptide 2 (UCP2), and emulsified with the immunoadjuvant Montanide, with potential immunomodulating and antineoplastic activities. Upon administration of microbiome-derived peptide vaccine EO2040, the peptides are taken up by and presented on dendritic cells (DCs) to T-cells. As the presented antigens display molecular mimicry with selected TAAs on colorectal cancer cells, a cytotoxic T-lymphocyte (CTL)-mediated immune response may be mounted against the cancer cells expressing the TAAs, thereby eradicating the cancer cells. UCP2 is able to activate the immune system to mount a T-helper 1 (TH1) CD4-positive T-lymphocyte immune response thereby further killing tumor cells.