Incidence of the disease has almost doubled every decade in the last 20 years in people under 50. Colibactin can trigger it.
After all, it is not just: a bacterial toxin can help explain the increase in colorectal cancer Among young adults – the second most frequent cancer in Portugal and the second largest cause of cancer death. It is always fatal.
A new study on April 23 at Nature suggests that colibactina It will be particularly relevant in cases diagnosed before the age of 40.
Colibactin is a genotoxin produced by certain intestinal bacteria, including some E. coli strains, and is known for damaging DNA.
The University of California researchers in San Diego analyzed fabric samples of nearly 1000 patients with colorectal cancer worldwide and found that about 50% Of early onset cases in individuals under 40 had a unique mutation in DNA associated with exposure to colibactin. Damage can start in childhood, in exposure to bacteria in the first 10 years of lifesuggest the results.
“This may mean that someone who acquires such mutations at the age of five may be predisposed to develop colorectal cancer decades earlier than expected,” explains the senior author of the study Ludmil Alexandrov, Ao.
Although the study does not prove causality, it raises important questions about how early childhood environments may influence the risk of cancer later. Scientists point to various plausible pathways for children’s exposure to bacteria producing colibatin, such as Early use of antibiotics, poor diets in fiber, Increased caesarean sections, reduced breastfeeding and microbial environments shared in day care centers.
Although colibactin has already been studied earlier in relation to colorectal cancer, previous research was usually concentrated in older patients or could not differentiate between early and late onset cases. This study is one of the first to associate toxin specifically with cancers in younger populations.
Other bacteria, such as the Fusobacterium nucleatumhave also been implicated in the progression of colorectal cancer. They can promote tumor growth and prevent immunological detection. If the colibactin can start the process, the F. nucleatum can contribute to its development.
Colorectal cancer should be the leading cause of cancer -related death in young adults by 2030 if current trends continue.
