Messages from gut bacteria crucial in colorectal cancer

Messages from gut bacteria crucial in colorectal cancer
 
Two studies have shown that mRNA from gut bacteria can control your risk of colorectal cancer, and even which type you get.
 
First(1), a team from the University of Minnesota took tissue from 44 patients with colorectal cancer – a sample from the area of the colon with cancer, and a further sample from a healthy area of colon tissue.
 
What they found was very clear. A huge number of host microRNAs are modified in the areas of cancer compared to the healthy areas. And the extent of these modifications is proportional to the abundance of certain microbes or pathogens in the gut. Put simply, the gut bacteria genomes exert an influence over the healthy cell microRNA and this can lead to colorectal cancer.
 
Principal study investigator Ran Blekhman, Ph.D., assistant professor, Departments of Genetics, Cell Biology and Development, and Ecology, Evolution, and Behavior, at the University of Minnesota said that the next step was to identify which correlations are causal, and whether or not they could be manipulated to arrest the cancer.
 
In a second study (2), this time by members of the University of Otago, and Massey University in New Zealand, patients with colorectal cancer had their subtypes related to the relative abundance of bacteria present for the first time in research. 34 tumours were classified into three subtypes. 
RNA analysis showed an overall enrichment of Fusobacteria and Bacteroidetes, but decreased levels of Firmicutes and Proteobacteria.
Then, by using non-human RNA-sequencing the researchers uncovered distinct bacterial communities associated with each molecular subtype. One subtype had high levels of 
Fusobacterium nucleatum, Parvimonas micra, Peptostreptococcus stomatis, Fusobacterium hwasookii and Porphyromonas gingivalis. A second subtype had high levels of Selenomas and Prevotella species, while a third had few significant associations. 
Go to: The role of Gut bacteria in Colorectal cancer
In another study(3) from Otago, a mutation in a common and normally helpful gut bacterium Bacteroides fragilis, seemed linked to colorectal cancer. 
150 healthy people, who had had a colonoscopy were monitored over a 15 year period. 79 per cent of those who developed the mutated bacterium also developed bowel cancer lesions. Frank Frizelle a New Zealand Bowel cancer expert and surgeon said that this research was a ‘game changer’. It’s just more evidence of rogue gut bacterium and their threat.
 

 

Chris Woollams, former Oxford University biochemist and a founder of CANCERactive said, “We have previously covered the SYNCAN study where Fusobacterium was shown to be the naughty bacterium implicated in most CRC. There could well be others. What is interesting is that in both these main studies, the scientists are talking about how to minimize the influence of the ‘bad’ gut bacteria, through such ’treatments’ as diet or even a vaccine. Fecal Transplantion may also be an option in the future"
Go to: Colorectal cancer - symptoms, causes and alternative treatments
 

Ref

1. https://www.ncbi.nlm.nih.gov/pubmed/29795787

2. https://www.researchgate.net/publication/319715269_Distinct_gut_microbiome_

 patterns_associate_with_consensus_molecular_subtypes_of_colorectal_cancer

3. https://www.odt.co.nz/news/dunedin/campus/university-of-otago/otago-bowel-cancer-breakthrough-could-bring-vaccine

 

2018 Research
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