Table 3.

Intratumoural microbiota that can produce a tumor-suppressive microenvironment

Intratumoural microbiota	Mechanism	Cancer	References
Fusobacterium nucleatum	Stimulation of anti-inflammatory myeloid cells in human CRC tissue by activating TIGIT and CEACAM1 inhibitory receptors, thereby impairing NK and T cell function	Colorectal cancer	[55, 83]
Firmicutes phylum Bacteroides phylum	Promoting T cell differentiation into Th17 and Th1 cells	Colorectal cancer	[84–86]
Listeria Monocytogenes	Transforming MDSCs into an immunostimulatory phenotype that produces IL-12	Breast cancer	[87]
Salmonella	Delaying angiogenesis by upregulating Cx43 and downregulating HIF-1α and VEGF	Melanoma	[57, 88, 89]