Table 1.
An overview on the most studied gut microbioma species involved in GI cancer.
| Site | Effect | Mechanism | References | |
|---|---|---|---|---|
| Neisseria elongate | Oral | ↓↓↓ pancreatic tumor | Promotes oral homeostasis. | [121] |
| Streptococcus mitis | Oral | ↓↓↓ pancreatic tumor | Promotes oral homeostasis. | [121] |
| Porphyromonas gingivalis (strain ATCC 53978) | Oral | ↑↑↑ pancreatic tumor | Promotes oral dysbiosis and inflammation. | [121] |
| Helicobacter pylori | Stomach, liver, intestine | ↑↑↑ gastric liver pancreatic colorectal tumor; ↓↓↓ esophageal tumor |
Immune-modulating effect through Th17 pathway; promoting factor for dysbiosis; not clear protective properties in esophageal tumor. | [67,80,97,111,142] |
| Helicobacter hepaticus | Liver | ↑↑↑ liver tumor | Directly damages DNA, through WNT and NF-κB signaling pathways in tumor cells; suppresses intra-tumor immunity in aflatoxin- and hepatitis C virus-induced HCC. | [97,100,101] |
| Streptococcus bovis | Intestine | ↑↑↑ colorectal tumor | Immune-modulating effect; symbiotic relation with tumor cells. | [79,89] |
| Bacteroidesfragilis | Intestine | ↑↑↑ progression colorectal tumor | Immune-modulating effect through TH17 pathway; promotion of WNT, NF-κB and STS-3 pathways; direct effect of BFT toxin. | [87,88,134,143] |
| Enterococcus faecalis | Intestine | ↑↑↑ colorectal tumor | Inflammatory effect through ROS production; increases risk of epithelial damage | [82,92] |
| Clostridium septicum | Intestine | ↑↑↑ colorectal tumor | Inflammatory effect; increases risk of infectious complications. | [83] |
| Fusobacterium spp. | Intestine | ↓↓↓ colorectal tumor; ↑↑↑ esophageal tumor. |
Immune-modulating effect. Esophageal dysbiosis marker. | [66,84,144] |
| Escherichia coli | Intestine, pancreas | ↑↑↑ colorectal and liver tumor; ↓↓ pancreatic tumor |
Direct epithelial invasion; production of nitrous compounds through eme-metabolism; promotes dysbiosis. | [85,86,102,145] |
| Lactobacillum spp. | Gastro intestinal apparatus | ↓↓↓↓ malignancies | Promotes gut homeostasis; anti-inflammatory effects. |
[54,55,56,76,110] |
| Bifidobacter spp. | Gastro intestinal apparatus | ↓↓↓↓ malignancies; ↓↓ immunotherapy side-effects |
Promotes gut homeostasis through competition with pathogens; anti-inflammatory effects. |
[54,55,77,110] |
| Clostridium cluster IV | Gastro intestinal apparatus | ↓↓↓↓ malignancies | Promotes gut homeostasis; anti-inflammatory effects. |
[55] |