Latest news with #Alexandrov
Newsweek
21-05-2025
- Health
- Newsweek
Higher Risk for Colorectal Cancer Linked to Bacteria
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Scientists have identified a strong link between childhood exposure to a bacterial toxin called colibactin and the rising incidence of early-onset colorectal cancer, according to an international study published in Nature in April. The research, led by Professor Ludmil Alexandrov of the University of California, San Diego, analyzed nearly 1,000 colorectal cancer cases from 11 countries, pinpointing distinct DNA mutations in younger patients whose exposure likely occurred before age 10. Newsweek reached out to Alexandrov via email for comment. Why It Matters Colorectal cancer was once considered mostly a disease of older adults, but cases in people under 54 have surged by 11 percent over two decades, now comprising one in five diagnoses in the United States and other high-income countries. Many younger patients lack the typical risk factors—such as family history, obesity, or sedentary lifestyle—prompting new urgency to understand hidden environmental contributors. The study's findings show how early microbial exposure can leave a "time bomb" of mutations, a report by UC San Diego said, fundamentally changing our understanding of cancer risk and offering potential for early detection or prevention strategies that could save lives as rates keep rising. A concept image depicting colon cancer. A concept image depicting colon cancer. Mohammed Haneefa Nizamudeen/Getty What To Know The study found that people under 40 were three to five times more likely to have colibactin-specific genetic changes than older adults with cancer, suggesting childhood bacteria could dramatically accelerate cancer risk. The research spotlighted colibactin, a genotoxin produced by certain strains of E. coli, a common gut bacterium. Colibactin acts as a so-called "weapon system" for bacteria competing in the intestinal environment and has been shown to damage the DNA of nearby human cells, initiating genetic changes that can progress to cancer, Alexandrov said in a report by NPR. Not all individuals carrying colibactin-producing bacteria develop cancer. Research shows that around 20 to 30 percent of the population harbors these strains, but their effect depends on factors such as the composition of a person's microbiome, dietary habits, and the presence of other environmental triggers. While the study identifies a significant association, causality has not been definitively established. Experts said other components, including rates of cesarean births, breastfeeding, antibiotic usage, and the consumption of highly processed foods, could impact the gut microbiome and the risks posed by bacteria like E. coli. Colibactin-linked cancers are also more common in the U.S. and Western Europe, where a higher frequency of risk factors, from dietary habits heavy in red meat to widespread antibiotic use, could be at play. Researchers are exploring whether probiotics that displace colibactin-producing strains might lower risk, and work is underway to develop stool tests that detect colibactin-related mutations as an early warning tool. Experts recommend traditional lifestyle measures such as maintaining a Mediterranean-style diet, regular activity, and not smoking, while urging awareness of early symptoms like abdominal pain, unexplained weight loss, or rectal bleeding. What People Are Saying Study author Professor Ludmil Alexandrov said in a report by SciTechDaily: "If someone acquires one of these driver mutations by the time they're 10 years old, they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60." Marcos Díaz-Gay, a co-author of the study, told UC San Diego Today: "Our original goal was to examine global patterns of colorectal cancer to understand why some countries have much higher rates than others. But as we dug into the data, one of the most interesting and striking findings was how frequently colibactin-related mutations appeared in the early-onset cases." What Happens Next Researchers plan to further investigate how children become exposed to colibactin-producing bacteria, evaluate the impact of environmental and dietary factors, and develop early detection tests.
National Geographic
16-05-2025
- Health
- National Geographic
Colon cancer is rising in young people. Finally, scientists have a clue about why.
As scientists question the rise in early colon cancer cases, a new study is offering some potential answers. Colored scanning electron micrograph (SEM) of a macrophage white blood cell (center) that is being destroyed by toxins released by E. coli bacteria (red). Some strains of E. coli release colibactin, a toxin which damages the DNA of cells, and may contribute to the development of colorectal cancer. Micrograph by Steve Gschmeissner, Science Photo Library Colorectal cancer should be on your radar: Today, one in five people under the age of 54 is diagnosed with the disease, marking an 11 percent uptick in this age group over the past two decades. What, exactly, is fueling the surge in younger patients has perplexed scientists and medical professionals alike. (Colon cancer is rising among young adults. Here are signs to watch for.) For years, however, experts have suspected that colibactin, a toxin produced by E. coli and other bacteria that can damage DNA, could be involved. Now, a new study published in Nature has identified a strong link between childhood exposure to colibactin and colorectal cancer in patients under the age of 40. Here's how the study expands scientists' understanding of the microbiome's influence on colorectal cancer development, plus how a focus on colibactin could pave the way for earlier detection and new prevention strategies. What researchers discovered in colon cancer patients The researchers initially designed the study to broadly explore why people in different countries develop colorectal cancer at different rates, so the colibactin observation was 'somewhat incidental,' says lead study author Ludmil Alexandrov, a professor of cellular and molecular medicine at the University of California, San Diego. He and his team analyzed blood and tissue samples from the tumors of nearly 1,000 colorectal cancer patients across 11 countries, including Canada, Japan, Thailand, and Colombia. They used DNA sequencing technology to identify cellular mutations, or genetic changes that can help cancer form, grow, and spread. 'Different carcinogens leave this characteristic pattern of mutations, which we call mutational signatures,' Alexandrov explains. 'The simplest example is if you smoke cigarettes, you get a specific pattern of mutations across your lung cells.' Alexandrov and his team found that people diagnosed with colorectal cancer under the age of 50 had a 'striking enrichment' of mutations associated with colibactin. The younger the person was, on average, the higher the prevalence of these signatures. Those diagnosed with colorectal cancer under age 40 were about three times more likely to have colibactin-driven mutations than those diagnosed after age 70. 'When we sequence cancers, we see this archeological record of everything that happened in that person's lifetime,' Alexandrov says. Meaning, scientists can figure out the approximate timing of when specific mutations took hold in the gut. The study's results suggest that the participants' colibactin exposure happened before they turned 10. This early 'hit' to the gut microbiome seemed to put people 20 to 30 years ahead of schedule for developing colorectal cancer, Alexandrov says. Rather than being diagnosed in their 60s or 70s, they faced the disease in their 30s or 40s. Cynthia Sears, an infectious disease expert and professor of oncology at the Johns Hopkins University School of Medicine, who was not involved in the study, believes the study was done 'carefully and thoroughly,' but also leaves questions unanswered. 'We don't understand the biology of these organisms and the circumstances that allow them to be mutational,' she says. Alexandrov agrees. He says this new study shows a 'strong association' between childhood colibactin exposure and early-onset colorectal cancer. However, proving that colibactin actually causes colorectal cancer would be 'very complicated.' How colibactin could lead to colorectal cancer Colibactin is a genotoxin—think of it as a weapon certain bacteria deploy to protect themselves against other microbes. Experts theorize that, in some people, these bacteria become dominant and then start hurting their hosts, Alexandrov explains. Once they colonize the colon, they can latch onto healthy tissues, attack cells, and generate DNA mutations. Fluorescence micrograph of human colon cancer cells in a three-dimensional extracellular matrix, where the cells organize into cancer organoids as they would in human tissue. Micrograph by Dr Torsten Wittmann, Science Photo Library A colored 3D computed tomography (CT) scan of the colon of a 54-year-old male patient, showing extensive narrowing (stenosis) in the left colon (highlighted, upper right), suggesting the presence of a cancerous lesion. Image by Zephr/Science Photo Library But not everyone with colibactin-producing bacteria winds up with colorectal cancer—estimates show 20 to 30 percent of people harbor these strains. So what's prompting the bugs to go rogue in certain individuals? 'We think something is happening to give them an advantage over the other bacteria,' Alexandrov says. He cites previous studies that suggest people in Westernized countries (particularly urban areas), like the U.S. and parts of Europe, tend to have a higher prevalence of colibactin-producing bacteria in their guts than those in more rural or non-industrialized regions. 'To me, this is a window of opportunity to zero in on environmental influences in different sectors of the world,' Sears says. In particular, evidence suggests that a Western diet—typically higher in red and processed meats, added sugar, and refined grains and lower in fruits and vegetables—is associated with a higher risk of colorectal cancer. As for the reason why colibactin, specifically, could be more 'mutagenic' in the setting this diet creates in the gut? 'We just don't have this information,' Sears says. The new study didn't analyze the participants' individual cancer risk or track changes in their environment or diet, so any combination of these components could be at play. Alexandrov and his team suspect factors that can substantially alter a person's immune system and microbiome in their earliest years, like whether they were born via a C-section or vaginally, took antibiotics, were breastfed or formula-fed, or were fed a lot of processed foods. (How your fiber intake impacts your colon cancer risk) Some colibactin-producing bacteria may also trigger an immune response that further injures the cells. Those are the strains that 'get us into trouble,' Sears says. But it's 'extremely complex' to figure out what makes these bacteria stick in different parts of the gut. 'The rectum is different than the sigmoid colon,' she explains. 'Each of these regions has a somewhat different biology and predilection to tumor formation.' Where the research goes from here Alexandrov and Sears agree that longitudinal data is needed. Ideally, researchers would follow people in early life, give them probiotics designed to target colibactin-producing bacteria, and then track whether participants develop the associated mutations, and thus, early-onset colorectal cancer. 'If we can create the right probiotic that would bump off the bad actors, that might be a prevention strategy that would be easy and not harmful to people,' Sears says. Alexandrov and his team are looking into future studies that explore this possibility. He also believes they could design a stool test that pinpoints colibactin-related mutations. If this DNA damage is detected in the test, then the individual would be encouraged to start colorectal cancer screening earlier—say, in their 20s versus their 40s. (Will a new colon cancer blood test replace your colonoscopy?) All that said, Sears believes focusing on colibactin alone likely isn't the 'holy grail' solution to the rise in early-onset cases. 'We don't want to be too short-sighted about the spectrum of the research that we do,' she says. Until we have more data, focusing on the lifestyle changes you can control is key; Sears points to eating a Mediterranean-style diet, staying active, quitting smoking, and cutting back on alcohol. Awareness is also paramount: Young adults—as well as many medical professionals—are quick to brush off colorectal cancer symptoms like persistent abdominal pain, unexplained weight loss, and rectal bleeding. As Alexandrov stresses, 'they should be aware that it may be something quite serious,' because the sooner the tumors are detected, the easier they will be to treat.
Yahoo
05-05-2025
- Health
- Yahoo
Scientists Discover Childhood Exposure to Common Bacteria May Trigger Early Colon Cancer
As a mother, hearing about rising cancer rates in young people is deeply concerning, but new research offers crucial insight into why colorectal cancer is increasingly affecting younger generations. Scientists have discovered that early childhood E. coli colon cancer connections may be stronger than previously understood. A groundbreaking study published in Nature reveals that exposure to colibactin, a toxin produced by certain strains of E. coli bacteria, before age 10 could dramatically accelerate the development of colorectal cancer later in life. This finding may explain the alarming trend of colorectal cancer diagnoses in people under 50, which have been increasing by 2.4% annually according to the American Cancer Society. Related: The research team, led by Professor Ludmil Alexandrov from UC San Diego, examined nearly 1,000 colorectal cancer genomes and found a distinct genetic fingerprint left by colibactin. This mutation signature was 3.3 times more common in patients with early-onset colon cancer compared to those diagnosed later in life. "If someone acquires one of these driver mutations by the time they're 10 years old," Alexandrov explained, "they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60." For parents, this research underscores the importance of understanding potential early childhood E. coli colon cancer risks. While not all E. coli strains produce colibactin, those that do can cause genetic mutations that may initiate cancer development years before symptoms appear. Related: Diet appears to play a significant role in this process. A separate study from the National Library of Medicine found that Western-style diets rich in red and processed meats and sugar increased the risk of colorectal cancer containing high amounts of the toxin-producing E. coli bacteria. This discovery "reshapes how we think about cancer," according to Alexandrov. "It might not be just about what happens in adulthood—cancer could potentially be influenced by events in early life, perhaps even the first few years." While more research is needed, these findings highlight the importance of childhood nutrition and gut health in preventing cancer decades later. For families, focusing on balanced diets lower in processed meats and added sugars may help reduce exposure to harmful bacteria strains associated with these genetic mutations. Up Next:
India Today
02-05-2025
- Health
- India Today
Could childhood bacteria be driving colon cancer in millennials?
Childhood exposure to a bacterial toxin in the colon may be triggering the increase in colorectal cancer cases among younger patients, a new study considered a disease of older adults, colorectal cancer is now on the rise among young people in at least 27 countries. Its incidence in adults under 50 has roughly doubled every decade for the past 20 for clues as to why, the researchers analyzed genes of 981 colorectal cancer tumors from patients with varying colorectal cancer risk levels who had early- or late-onset disease in 11 countries. DNA mutations in colon cells that are known to be caused by a toxin produced by Escherichia coli, called colibactin, were 3.3 times more common in adults who developed colon cancer before age 40 than in those diagnosed after age patterns of mutations are thought to arise when children are exposed to colibactin before age 10, researchers reported in mutation patterns were particularly prevalent in countries with a high incidence of early-onset cases.'If someone acquires one of these... mutations by the time they're 10 years old, they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60,' study leader Ludmil Alexandrov of UC San Diego said in a every environmental factor or behavior we study leaves a mark on our genome,' said Alexandrov. 'But we've found that colibactin is one of those that can. In this case, its genetic imprint appears to be strongly associated with colorectal cancers in young adults.'The researchers have found other mutational signatures in colorectal cancers from specific countries, particularly Argentina, Brazil, Colombia, Russia and suggests that local environmental exposures may also contribute to cancer risk, they said.'It's possible that different countries have different unknown causes,' study co-author Marcos Diaz-Gay of the Spanish National Cancer Research Center in Madrid said in a statement.'That could open up the potential for targeted, region-specific prevention strategies.'
Yahoo
29-04-2025
- Health
- Yahoo
Could This Toxin Be Behind the Rise of Early Onset Colon Cancer?
It's still not clear why colon cancer cases continue to rise among young people — but researchers may have come across a lead. A new study has identified a potential culprit: a toxin called colibactin that's capable of altering DNA. Scientists found that exposure to this gut bacteria in early childhood can lead to mutations within colon cells, which could be what's causing so many young adults to develop colorectal cancer (CRC). Here's a closer look at this fascinating new research and what it tells us about this potential carcinogen. The study, which was published last week in Nature, examined tissue samples from nearly 1,000 CRC patients spread across four continents. The team discovered that colibactin leaves behind a specific pattern of DNA mutations, and that patients who developed the disease before the age of 40 were more than three times as likely to exhibit this genetic hallmark than those who were diagnosed after 70. The researchers were also able to trace when these mutations arose, and the scientists believe that they're most likely acquired by the age of 10. That could put these patients 'decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60,' the study's senior author, Ludmil Alexandrov, says. Colibactin is a bacterial toxin that's produced by certain strains of Escherichia coli, or E. coli, and other gut bacteria. Previous studies have shown that the toxin has the potential to damage the DNA of cells within the colon. But this latest research raises the question: If colibactin is triggering CRC-related mutations in childhood, why are more children being exposed to the toxin? Alexandrov tells NBC that 'there are several plausible hypotheses.' One is early antibiotic use, 'which may allow these strains to establish more easily,' he says. Another contributing factor could be the increase in ultraprocessed foods in our diets, the decrease in fiber, and rising rates of C-section births. 'Collectively, these shifts may be tipping the balance towards early-life acquisition of these microbes,' he says. Alexandrov and his team are in the process of developing stool tests to detect colibactin-related mutations and are investigating whether probiotics could help eliminate harmful strains of bacteria. The post Could This Toxin Be Behind the Rise of Early Onset Colon Cancer? appeared first on Katie Couric Media.
