In a groundbreaking study, scientists have identified a potential cause of the rising incidence of colon cancer in young people, challenging the long-standing belief that the disease primarily affects older adults. Researchers, led by Professor Ludmil Alexandrov at the University of California, San Diego, have pinpointed a link between early-life exposure to a specific strain of E. coli bacteria and the development of colorectal cancer in individuals under 50.
Historically, colon cancer has been considered a disease of aging, with the majority of cases occurring in individuals over the age of 50. However, in recent years, there has been a concerning rise in cases of early-onset colorectal cancer, particularly among people in their 20s, 30s, and 40s. This trend has been especially noticeable in countries like the United States and the United Kingdom.
To understand the underlying causes, the research team analyzed the DNA of 981 colorectal tumors from patients in 11 countries. Their findings revealed that colibactin-associated mutations, which are linked to a specific toxin produced by E. coli, were significantly more prevalent in patients under 40 compared to those over 70. This toxin, known as colibactin, is produced by certain strains of E. coli bacteria and is known to damage the DNA of colon cells, potentially leading to cancer.
The study suggests that exposure to colibactin likely occurs during childhood, with the bacteria being commonly contracted through undercooked meat, raw produce, and contaminated water. Leafy vegetables such as spinach are also vulnerable to contamination through polluted irrigation water or interaction with animals in the field. Additionally, unpasteurized dairy products, including raw milk, and uncooked fruits and vegetables, such as apples and cucumbers, present significant risks, as they can serve as breeding grounds for harmful bacteria.
Research indicates that colibactin-producing E. coli strains are commonly found in the intestines of children, with around 30-40% of children in the U.S. and U.K. carrying these bacteria. The mutations associated with colibactin were particularly prevalent in countries with high rates of early-onset colorectal cancer, underscoring the connection between microbial exposure and the disease’s increasing incidence among younger populations.
The study’s authors propose that factors such as increased cesarean births, antibiotic use in childhood, and the growing consumption of ultra-processed foods may contribute to the rising exposure to colibactin-producing bacteria. These environmental and microbial risk factors may be altering the gut microbiome and increasing the likelihood of colon cancer later in life.
Dr. Alexandrov, the senior author of the study, emphasized the significance of these findings, noting that the mutation patterns observed in the tumors act as a “genetic record” of early-life exposure to harmful bacteria. This suggests that the damage leading to cancer may occur long before adulthood, possibly even before the age of 10.
These revelations have important implications for cancer prevention. The study highlights the need for further research into the environmental and microbial factors that contribute to colorectal cancer. One potential preventive strategy could be the use of probiotics to help reduce the presence of harmful bacterial strains in the gut, potentially lowering the risk of developing colon cancer.
This research also calls for greater awareness of the role that early-life exposure to bacteria may play in the development of cancer. With projections indicating that colorectal cancer could become the leading cause of cancer-related deaths among young adults by 2030, understanding these early-life influences and identifying preventive measures could be crucial in combating the growing incidence of the disease.
Ultimately, this study challenges our understanding of cancer’s origins and opens the door for new approaches to prevention, focusing on microbial exposure and its long-term effects on health.
