Gut Bacterial Microbiome Profiles Associated with Colorectal Cancer Risk: A Systematic Review and Meta-Analysis

Abstract

Objective Recent studies have shown a potential link between gut microbiome and colorectal cancer (CRC). Initially, a wide array of research into this topic was discovered from the past decade, illustrating a keen interest in the potential causal relationship between the gut microbiome and CRC. However, the cancer research community is lacking a summarised systematic review of this kind which aims to explore the evidence linking the human gut microbiome to risk of CRC. Design This systematic review was carried out with two independent reviewers assessing the database outcomes from Medline and EMBASE during May 2020. A meta-analysis was undertaken studying the link between Helicobacter pylori and CRC; processed through Stata. Results 31 papers were included in the systematic review, followed by 12 for the meta-analysis. From these papers, Fusobacterium and Bacteroides were reported most frequently as enriched in CRC versus control. The meta-analysis showed an Odds Ratio of 1.49 (95% CI 1.19 - 1.86), including a total of 20,001 events. This meta-analysis concluded that H. pylori infection significantly increases the risk of CRC, albeit with evidence of publication bias. Conclusions Bacteria have been discovered to increase the risk of CRC, however a definitive causal relationship cannot be concluded or excluded using case-control studies. To fully understand the potential link of the bacteria listed, alterations in research design and execution are required. The assessment found a need for a large-scale cohort study conducted over a significant period of time to thoroughly evaluate the potential relationship between gut microbiome and CRC risk.

Amination Potentially Augments the Ameliorative Effect of Curcumin on Inhibition of the IL-6/Stat3/c-Myc Pathway and Gut Microbial Modulation in Colitis-Associated Tumorigenesis

“…Decreased Bacteroides have been reported in gut microbial dysbiosis, associated with increasing serum proinflammatory responses and C-reactive protein levels . While enrichment of some members of the genus Bacteroides , such as Bacteroides fragilis, has been reported by a previous study, Bacteroides thetaiotaomicron was the member enriched in the LAC group (data not shown). However, no studies have explored the relationship between the Eubacterium nodatum group and colitis or CRC.…”

Gut Microbial and Associated Metabolite Markers for Colorectal Cancer Diagnosis

“…These findings are consistent with the findings of a systematic review conducted by Russ et al, which investigated the association between the human gut microbiome and the risk of CRC. The study found that Fusobacterium and Bacteroides were the most enriched microbial species in CRC compared to HC [ 76 ]. Another systematic review found nine fecal microbiotas ( Fusobacterium , Enterococcus , Porphyromonas , Salmonella , Pseudomonas , Peptostreptococcus , Actinomyces , Bifidobacterium, and Roseburia ) to be associated with colorectal neoplasia [ 77 ].…”

A systematic review of the colorectal microbiome in adult cystic fibrosis patients

“…Colorectal dysbiosis in CF has been linked with increased risk of CRC [14][15][16]. Historically, CF microbiome research has focused on the paediatric population which demonstrated that CF children have reduced GI microbial diversity and fewer protective shortchain fatty acid (SCFA) producing bacteria [17][18][19].…”