An international team of scientists, led by the University of California in San Diego (United States), has identified a possible cause of the worrying increase in colorectal cancer in adults under 50: an early infection by the Bacterial toxin colibactin, produced by certain intestinal strains.
Published in Nature magazine, the study offers new keys on how this toxin can modify the DNA of colon cells, leaving behind a Genetic footprint recognizable known as mutational firm. These alterations, according to researchers, would be up to 3.3 times more frequent in patients diagnosed before the 40 years that in those over 70.
“Each carcinogenic factor leaves a unique mutational firm, as a historical record in the genome,” explains Marcos Díaz Gay, head of the new Digital Genomics Group of the National Oncological Research Center (CNIO) and first work signer. “Colibactin leaves a clear brand, especially in young patients.”
The research analyzed the genomes of 981 patients with colorectal cancer in eleven countries, revealing a strong correlation between these mutations and early appearance cases. This trend is especially visible in regions with a high incidence of youth cancer, such as Argentina, Brazil, Colombia, Russia or Thailandwhich also suggests an interaction with environmental factors not yet identified.
Early colonization, colorectal cancer
Until now, there was no clear cause for the increase of this type of cancer in young adults. Many of them lack family history and present few traditional risk factors, as obesity or hypertension. According to the authors, the acquisition of mutations linked to colibactin in childhood could advance the appearance of cancer up to two decades.
“This radically changes our way of thinking about cancer,” he says Ludmil Alexandrov, main author of the study. “It is no longer enough to observe adult life: the first decades, even the first years, can be decisive.”
The finding opens the door to new preventive strategies. The team already works on the development of early detection test, based on the analysis of feces, as well as in the possible use of probiotics to safely eliminate harmful bacterial strains.
Threatened investigation
This ambitious study is part of the Mutographs of Cancer – Cancer Research UK Grand Challenge program, an international collaboration between reference centers such as the Wellcoma Sanger Institute (United Kingdom) and the International Agency for Cancer Research.
However, its continuity is threatened. Alexandrov has warned about the potential impact that the budget cuts to the National Health Institutes (NIH) of USA They could have the investigation.
«This work requires dozens of millions of dollars. If the cuts are confirmed, it would be a hard blow not only for the US, but for the global research against cancer »he warns. “We are talking about discoveries that can transform the future health of millions of children worldwide.”
