The incidence of colorectal cancer and the deaths associated with it are increasing in young adults, as various studies have revealed, as one published in 2024 in Annals of Oncology that warned of an increase in mortality rates for this type of tumors in the European Union and the United Kingdom in people aged 25 to 49.
Scientists are investigating the causes and now an international team of researchers, led by the University of California in San Diego with the participation of the CNIO (National Center for Oncological Research) has identified a possible microbial responsible for the worrying increase in cases of colorectal cancer in young people: a bacterial toxin known as colibactin.
This toxin is produced by certain strains of They exhibited chill that are present in the colon and the rectum and is able to alter the DNA. Scientists have discovered that exposure to colibactin during childhood leave a characteristic genetic firm in the colon cells that could Increase the risk of developing this type of cancer before 50 years. The findings have been published in the magazine Nature.
The researchers analyzed the genome of 981 tumors of patients with colorectal cancer, both of early appearance, and late, in 11 countries with different incidence rates. The results showed that the mutations associated with colibactin were 3.3 times more frequent in patients under 40 years of age than in those diagnosed from 70. In addition, these mutations were more common in countries with the highest number of early cases.
“These mutation patterns are a kind of historical record in the genome and point to early exposure to colibactin as a driving force behind the early appearance disease,” said Ludmil Alexandrov, principal author and professor at the University of California San Diego, in a note published by the center.
Early exposure to colibactin as a risk factor
Although previous investigations had already detected mutations related to colibactin in 10-15% of cases, the new study is the first to find a Clear and significant connection with early appearance cancers. The situation worries, since colorectal cancer – which was traditionally associated with older people – is increasing among young people in at least 27 countries. In the last two decades, its incidence in children under 50 has doubled every ten years, and estimates indicate that It could become the main cause of cancer death in young adults around 2030.
The most disconcerting is that many young patients do not present familiar history or known risk factors, such as obesity or hypertension. This has led researchers to take into account the possible involvement of hidden environmental or microbial exhibitions, hypothesis that this study begins to confirm.
“If someone acquires one of these driving mutations before he turned 10 could develop colorectal cancer decades before, at age 40 instead of 60”
The analysis also allowed molecular mutations, confirming that many of them appear in the early stages of tumor development, even in the first ten years of life. It is estimated that 15% of the so -called driving mutations (driver mutations) – Key genetic alterations for the appearance of cancer – are related to colibactin.
“If someone acquires one of these driving mutations before turning 10,” said Alexandrov, “could develop colorectal cancer decades before, at 40 instead of at 60.” This means that these bacteria could be installed silently in children’s intestines and causing molecular changes long before the first symptoms appear.
Despite the revealing of the findings, researchers warn that a direct causality relationship cannot be established yet. Current research has opened new questions: how exactly is exposure to these bacteria during childhood? Do the diet, the environment or certain life habits influence? Would it be possible to eliminate these strains through probiotics? The team also works on early detection tests based on stool samples, which would identify mutations related to colibactin.
“To investigate our hypotheses more thoroughly and develop safe and ethical interventions, we will need dozens of millions of dollars,” said Alexandrov. “This research has important implications for child health Future worldwide. Without proper support, it will be difficult to fully understand and address the problem, ”concludes Alexandrov.
Julian Peto, Professor of Epidemiology at London School of Hygiene & Tropical Medicine (United Kingdom), which has not participated in the study has pointed out in statements to Science Media Center United Kingdom that “the observation that colibactin firms are more common in young colorectal cancers is not a conclusive evidence that the increase in exposure to colibactin is An important cause of the recent increase in colorectal cancer in successive generations born since the 1950s. ”
“An equally plausible explanation of these data is that the incidence of colorectal cancers (CCR) caused by early exposure to colibactin (such as CCR There has been a secular increase in the proportion of CCR with these firms, ”concludes this expert.
Source: www.webconsultas.com