Table 1.

Types of cancer induction and mechanisms of carcinogenesis induced by different microbiota.

Cancer	Bacteria inducing cancer	Mechanisms of carcinogenesis	References
Gallbladder cancer	Salmonella typhi	Changes in the sequence of p53 gene; activation of protein kinase; cytolethal distending toxin B (CdtB); biliary deoxycholate; cholic acid derivatives; 5-alpha,6-alpha-epoxide cholesterol; upregulation of the PI3K pathway	[8, 10–13]
Lung cancer	Chlamydia pneumoniae	Alteration in apoptosis and/or cell programming signalling; overexpression of miRNA-328; by stimulating lung-resident γδ T cells; development of Myd88-dependent IL-1b and IL-23; generation of reactive oxygen species; increased secretion of cytokines, IL-8, IL-10, and TNF	[5, 19–24]
Colorectal cancer	Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis, Enterococcus faecalis, Clostridium septicum, Fusobacterium spp., and Escherichia coli	Secretion of Bacteroides fragilis toxin; activation of NF-μB; expression of IL-17A, and TNF-α; β-catenin expression, induction of IL-17R, NF-κB, and Stat3 signals; induction of the gene expression of colibactin (clbB) and Bacteroides fragilis toxin (BFT), increased colonial interleukin-17, and colonic epithelial DNA damage	[69, 72–75]
Breast cancer	Methylobacterium radiotolerans, Sphingomonas yanoikuyae	Microbiota secretes bioactive metabolites including estrogens, short-chain fatty acids, amino acid metabolites, or secondary bile acids; dysbiosis	[78, 79]
Bladder cancer	Staphylococcus albus hemolytic, Staphylococcus aureus, Klebsiella spp., Proteus mirabilis, and E. coli	Formation of N-nitrosamines; DNA methylation; reactive chemical species	[83–87]