Fessler et al. [124] summarized the potential biological mechanisms of microbiome-mediated immune modulation: (1) bacterial translocation to different body districts may stimulate the immune response by providing microbial-derived, conserved antigens; (2) cross-reactive T cells primed against bacterial antigens might exert anti-tumor effects; (3) gut bacteria can release soluble immunomodulatory factors (IL-12, IFN-γ, and TNF-α) that then disseminate systematically and can activate dendritic cells. This evidence concerns the gene IFNG and neoplasm.