Colorectal cancer, originating in the colon or rectum, has seen a troubling increase in cases among young people, particularly those under 55.
Recent research published in the journal Nature has identified a potential contributor to this rise—a harmful bacteria known as colibactin.
Colibactin is categorized as a genotoxin and is produced by specific strains of E. coli and other bacteria.
Ludmil Alexandrov, a researcher at the University of California San Diego, describes colibactin as a ‘weapon system’ used by bacteria to fend off competitors.
This bacterial defense mechanism inadvertently harms our gut cells by damaging their DNA.
As a result, this may lead to colorectal cancer development.
While scientists typically find mutations associated with colibactin in about 15% of colon cancer cases, Alexandrov’s team discovered a much higher prevalence among younger patients.
In their analysis of nearly 1,000 patients worldwide, they noticed that individuals under the age of 40 exhibited three to five times more mutations compared to those over 70.
Alexandrov notes that evidence suggests these bacteria may have released the toxins in the guts of cancer patients during their childhood.
Their estimates suggest that this occurrence could take place within the first decade of life, potentially leading to cancer diagnoses in the 20s or 30s instead of later.
Though the research does not definitively prove colibactin as the cause of early-onset colon cancer, the association is compelling.
Christian Jobin, a microbiome researcher at the University of Florida, emphasizes that this study builds on years of research, including animal experiments that demonstrated colibactin’s cancer-driving capabilities.
However, it raises significant questions about the underlying triggers for these bacteria’s harmful behavior.
Jobin points out that strains of E. coli have existed for eons; thus, humans are not newly infected.
About 20% to 30% of people carry these E. coli strains in their guts, yet modern environmental factors may alter the way these microbes behave.
Alexandrov speculates that factors such as birth methods, breastfeeding, and antibiotic use might influence these microbe behaviors, contributing to the increasing colorectal cancer rates among younger populations.
Jobin expands on this notion by suggesting that other bacteria and genotoxins could also play a significant role in colorectal cancer, stating, ‘I don’t think colorectal cancer is caused by a single bacteria producing one genotoxin.’
This complexity hints at the multifactorial nature of cancer development, underscoring that it is unlikely that a simple cause-and-effect scenario fully explains the rise in cases.
As the research continues to unfold, it beckons a deeper investigation into the intricate relationship between our gut microbiome and cancer.
Understanding these connections could be vital in formulating preventive strategies against early-onset colorectal cancer.
In conclusion, the alarming increase in colorectal cancer among young adults emphasizes the urgency of exploring environmental and microbial interactions that could lead to new insights in cancer prevention.
Will Stone, reporting for NPR News.
image source from：https://www.npr.org/2025/04/24/nx-s1-5374086/toxin-may-be-factor-in-rise-of-colonrectal-cancer-in-younger-people-study-finds
