We believe that the scientific and translational relevance of this work is threefold. First, it provides additional experimental evidence on the influence of microbiome-induced T cell immunity in tumor progression. While microbiome can exert anti-tumorigenic effects through other mechanisms, the “fortuitous” elicitation of cytotoxic T cells cross-reacting with immunogenic tumor-specific neoepitopes is here experimentally demonstrated. Second, this work uncovers a novel biological function of OMVs, which extends to cancer immunity. The capacity of microbiome-release vesicles to contribute to tumor inhibition further underlines how inseparable evolution has made mammals and their microbiota. Finally, this work suggests a new approach of personalized cancer immunotherapy whereby probiotic bacteria and/or their OMVs are delivered orally once engineered with properly selected tumor-specific T cell epitopes. From now to the end of the project our objective is to provide additional experimental evidence of the role of molecular mimicry. Different mouse tumor models will be tested and different therapeutic and prophylactic modalities will be explored.