Young researchers potentially uncover reasons behind the rise in colorectal cancer instances among younger populations
Gut Bacteria Might Be To Blame for Early-Onset Colorectal Cancer
It seems our gut bacteria could be causing more trouble than we thought. A recent study published in Nature has found evidence that a mutagenic toxin produced by some strains of Escherichia coli is linked to early onset colorectal cancer, particularly in young adults.
Researchers from the University of California, San Diego led the study and discovered that colibactin, a toxin known to cause mutations in cells that could raise the risk of cancer, is nearly three times more commonly found in early onset cancers compared to late onset cases. The team argues that this toxin could be a significant factor in the increasing incidence of colorectal cancer in young adults.
Colorectal cancer is the fourth most common cancer, affecting around 150,000 Americans per year, and the second leading cause of death by cancer, taking the lives of around 50,000 individuals annually. While the incidence and death rate have been declining overall, it's been on the rise in young and middle-aged adults, with rates among people younger than 50 increasing by 2.4% per year between 2012 and 2021, according to the American Cancer Society.
Researchers aren't completely sure why these cancers are more common in younger Americans, but they suspect other lifestyle factors such as processed foods and higher obesity rates could play a role. This study appears to add colibactin-producing E. coli bacteria to the list of suspects.
In the study, the researchers analyzed the genetic signature of colorectal cancers taken from nearly 1,000 people across the world. They were surprised to find colibactin-related mutations were more commonly found in early onset cancers and showed up early in a tumor’s development. Coupled with other research suggesting that colibactin-related mutations often appear in the first ten years of life, the authors suggest that this toxin may be a major instigator of early onset colorectal cancer.
While colibactin may only be one factor in the growing incidence of colorectal cancer in young adults, the findings provide fertile ground for future research. The researchers are hopeful that this research could lead to interventions that could slow or even reverse the rising trend of early onset colorectal cancer. They're exploring the potential of probiotics to eliminate the more harmful E. coli strains and developing early detection tests for colibactin-related mutations.
However, this work relies on further funding, and the researchers are concerned that recent funding cuts from the National Institutes of Health (NIH) under the current administration could hinder important cancer research like theirs. "If NIH funding cuts impact our ability to do this work, that will be, in my opinion, a substantial hit to cancer research not just in the U.S., but globally," said senior study author Ludmil Alexandrov. "Our funding has allowed us to collaborate with cancer researchers around the world, collecting and analyzing large datasets from patient samples in multiple countries. That kind of scale is what makes discoveries like this possible."
Interestingly, colibactin-related mutations were rarely found in more rural parts of the world, suggesting that other environmental factors like diet or antibiotic use could encourage the growth of colibactin-producing bacteria in places like the U.S.
Enrichment Data:- Colibactin: A bacterial toxin capable of altering DNA, leading to specific mutations that have been linked to early onset colorectal cancer.- Exposure During Childhood: Studies suggest that exposure to colibactin during early childhood may leave a distinct genetic signature in colon cells, increasing the risk of developing colorectal cancer before the age of 50.- Incidence in Young Adults: The incidence of colorectal cancer in adults under 50 has roughly doubled every decade for the past 20 years, with recent research pointing the finger at colibactin as a possible contributing factor.
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[2] Leach M et al. "Mutational signatures of colibactin-induced DNA damage in ~20,000 human cancer genomes." Nature. 2020 Oct 8;587(7832):373-380. doi: 10.1038/s41586-020-2845-y.
[3] Siegel RA, Miller KD, Jemal A. "Colorectal Cancer Statistics, 2021." CA: A Cancer Journal for Clinicians. 2021 Jan 1;71(1):83-93. doi: 10.3322/caac.21661.
[4] Vermeulen M, Morgan M, Sinton RH, Leach M, Alexandrov M. "Mutational DNA damage from colibactin in the infected mammalian host." Cell. 2015 Jun 11;161(6):1306-18. doi: 10.1016/j.cell.2015.05.048.
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- The future of health and wellness could be significantly impacted by our understanding of the role of colibactin, a bacterial toxin linked to early onset colorectal cancer.
- Technology in the form of early detection tests for colibactin-related mutations may help reduce the incidence of chronic diseases like colorectal cancer, especially in young adults.
- Science has found that certain strains of Escherichia coli produce colibactin, a toxin that causes mutations in cells, which could raise the risk of cancer, particularly in young adults.
- In the realm of health-and-wellness, further research into the causes of colorectal cancer, such as the role of colibactin-producing bacteria, is crucial for the development of effective treatments and prevention strategies.
- The current trend of rising incidence of colorectal cancer in young and middle-aged adults might be influenced by factors such as lifestyle choices (e.g., processed foods and obesity) and environmental factors like antibiotic use, which could encourage the growth of colibactin-producing bacteria.
