Gut Microbiota: Detectors of early-stage Colorectal Cancer?

colon cancer
May 17, 2019 0 Comments

According to the World Cancer Research Fund International, by 2035, 2.4 million people will be diagnosed with colorectal cancer(commonly called bowel cancer) worldwide, mostly in developed countries. This cancer is ranked as the third common kind of cancer and the risk of its development is to the scale of 1 person in every 20 i.e.,5% boasting to be one of the three main reasons of deaths caused due to cancer.

Colon cancers are generally random in nature, which means they are sporadic or not genetically inherited. As a matter of fact, the living conditions, lifestyle and the environment are major causative factors which play a humungous role in the birth and development of bowel cancer, the earlier this cancer is detected better are the results. Till date, a colonoscopy the best standard for early detection of colorectal cancer remains to be a colonoscopy due to the virtue of providing the best possibly known view of the entire inner colon but as it is highly many adults skeptical of having to undergo this procedure. But, with progress in science, a  team of researchers may be credited with a completely novel and non-invasive technique for detection which involves gut microflora, this can be used efficiently as an aide to colonoscopies and certain such other tests.

The co-author of the study published in Molecular System Biology  – Julien Tap, a data analyst and microbial ecologist for the MetaGenoPolis project stated that the different test groups follow the hypothesis that our gut microbiota- clearly an important factor for our health, may have a major role to play in colon cancer. Past studies have shown that variations in the composition of these microflorae have been a reported cause of obesity, inflammatory bowel disease (IBD) and colorectal cancer. Although, these tiny organisms have never been brought to use for the detection of early-stage tumors.

For this, the researchers took stool samples from 61 healthy individuals, 53 people with chronic colon or rectal cancer and 42 precancerous intestinal polyps’ patients. The catch here was that scientists had asked the test subjects to provide the samples weeks before they underwent bowel cleansing for colonoscopy. This was because they were of the opinion that it could affect the composition of the intestinal microflora thus, leading to bias.

 

Characterization of the gut microflora from the stool samples of patients was done by undergoing stool DNA sequencing and bioinformatics analysis, they observed various features of the microbial population in each group. Information was also collected for BMI, age and ethnicity, these happen to be the three basic and most common factors influencing colorectal cancer.

Results highlighted that several populations of microflora that are linked to adenomas and carcinomas showed a contrast of growth as well as that of decline. A study conducted in 2013 by Kostic and team, indicates the catalysis offered by Fusobacterium nucleatum to cause intestinal tumourgenesis and also regulate the tumor-immune microenvironment. They found that some specific subspecies of Fusobacterium nucleatum are specially developed in the colon of cancer patients.  This was validated with an independent exanimation of 335 patients from different parts of the world.

The aim is to use the aforementioned gut microflora along with currently used screening procedures, such as Faecal Occult Blood Test (FOBT). The accuracy to detect the occurrence of precancerous and cancerous lesions is said to be enhanced on combining both methods on the subjects’ demographic data.

If the results produced affirmative in the majority of the population of the study, it may give rise to a new non-invasive stool test efficiently and effectively screens for colon cancer and also precancerous lesions. Tap claims that the future is where we can see sequencing our DNA and our metagenomes with the help of a pen-like tool, so that all observations of the study could be translated into a recurring service in local labs, with reduced expenses.

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