Latest news with #LudmilAlexandrov
Yahoo
06-07-2025
- Health
- Yahoo
Air Pollution 'Strongly Associated' With DNA Mutations Tied to Lung Cancer
Lung cancer cases are on the rise in non-smokers around the world, and air pollution could be an insidious, contributing factor. A genome study has now found that outdoor smog and soot are strongly associated with DNA mutations related to lung cancer – including known drivers seen in smokers, and new ones unique to non-smokers. The more pollution someone was exposed to, the more mutations scientists found in their lung tumors. The findings don't mean that air pollution is directly causing lung cancer, but they do contribute to evidence suggesting that possibility. Related: "We're seeing this problematic trend that never-smokers are increasingly getting lung cancer, but we haven't understood why," explains biomolecular scientist Ludmil Alexandrov from the University of California San Diego (UCSD). "Our research shows that air pollution is strongly associated with the same types of DNA mutations we typically associate with smoking." The extensive international analysis examined the cancer genomes of 871 individuals from four continents, all of whom had lung cancer despite never having smoked and who had not yet received cancer treatment. Those who lived in regions with high levels of air pollution were significantly more likely to have TP53 mutations, EGFR mutations, and shorter telomeres. Abnormal TP53 and EGFR genes are hallmarks of lung cancers, especially those driven by the SBS4 DNA mutation, and shorter telomeres are linked to accelerated aging. In the current study, non-smokers who lived in areas with higher air pollution were nearly four times more likely to exhibit SBS4 signatures as those who lived in regions with cleaner air. By contrast, exposure to secondhand smoke, which is a known cancer risk, showed only a slight increase in genetic mutations. "If there is a mutagenic effect of secondhand smoke, it may be too weak for our current tools to detect," says geneticist Tongwu Zhang from the US National Cancer Institute (NCI). Not so for air pollution or tobacco smoking: both were strongly linked to DNA mutations. Today in the United States, people who have never smoked or who have smoked fewer than 100 cigarettes in their lives make up about 10 to 20 percent of lung cancer cases. Scientists have long suspected that air pollution could be a contributing factor, but exactly how fine particulate matter in the air compares to tobacco smoking or secondhand smoke exposure remains unclear. Some studies suggest that breathing polluted air is on par with smoking a pack a day, and yet these conclusions are mostly based on observational analyses. The current study digs further by looking at some of the molecular mechanisms that may be at play. It compared the lung cancer genomes of the 871 non-smokers with tumors from 345 smokers, to find similarities and differences. The majority of non-smokers with lung cancer had adenocarcinomas (the most common type of lung cancer), and nearly 5 percent of those tumors showed the SBS4 mutational signature. In addition, 28 percent of non-smokers showed a new signature called SBS40a, which wasn't found in tobacco smokers. Strangely, the cause of this particular mutational driver was unknown, but doesn't seem to be environmental in nature. "We see it in a majority of cases in this study, but we don't yet know what's driving it," says Alexandrov. "This is something entirely different, and it opens up a whole new area of investigation." The current research relied only on regional air pollution levels, which means it can't say how much any one individual was directly exposed to fine particulate matter in the air. Participants who said they had never smoked may have also smoked more than reported. These limitations notwithstanding, the overall findings align with other evidence indicating that soot or smog may trigger tumor growth in a similar way to cigarette chemicals. "This is an urgent and growing global problem that we are working to understand regarding never-smokers," says epidemiologist Maria Teresa Landi from the NCI. The team now hopes to expand their study to include cancer genomes from a more diverse, global cohort. The study was published in Nature. FDA Issues Warning Over Dangerous 'Gas Station Heroin' Substance Mysterious Leprosy Pathogen Has Lurked in The Americas For 4,000 Years Massive Review Finds No 'Safe' Level of Processed Meat Consumption
Yahoo
03-07-2025
- Health
- Yahoo
Air pollution and herbal medicines could be behind lung cancer in non-smokers, study finds
Air pollution and traditional herbal medicines could be major risk factors contributing to the development of lung cancer in people with no history of smoking, a groundbreaking new study has found. While smoking is a major risk factor for lung cancer, rates of the malignancy appear to be increasing among those who have never smoked, even with tobacco use declining globally. Previous studies have shown that lung cancer disproportionately affects non-smoking women, particularly those with Asian ancestry, and is more prevalent in East Asia than in Western nations. Now, a new study, published on Wednesday in the journal Nature, provides compelling evidence that air pollution and herbal medicines could be behind genetic mutations linked to the development of lung cancer in non-smokers. 'We are seeing this problematic trend that never-smokers are increasingly getting lung cancer, but we haven't understood why,' said Ludmil Alexandrov, an author of the study from the University of California San Diego. 'Our research shows that air pollution is strongly associated with the same types of DNA mutations we typically associate with smoking.' Most lung cancer prevalence studies haven't separated data of smokers from that of non-smokers, providing limited insights into potential causes in those patients. The latest study collected data from never-smokers worldwide and used genomics to find environmental factors likely behind these cancers. 'This is an urgent and growing global problem that we are working to understand regarding never-smokers,' said Maria Teresa Landi, co-author of the study from the US National Cancer Institute. While previous studies have shown a potential link between air pollution and lung cancer in never-smokers, the new research goes further by revealing a genomic link. In this comprehensive study, scientists analysed lung tumours from 871 never-smokers living in 28 regions with different levels of air pollution across Africa, Asia, Europe and North America. Researchers used genome sequencing methods to identify distinct patterns of genetic mutations which act like molecular fingerprints of past exposures. They then compared the genomic data with pollution estimates based on satellite and ground-level measurements of fine particulate matter. This helped them estimate long-term exposure of the patients to air pollution. The study found that never-smokers living in more polluted environments had significantly more mutations in their lung tumours, particularly the kinds which directly promote cancer development. Scientists also found more molecular signatures in this group, which are linked to cancer and serve as a record of all past exposures to mutation-causing environmental factors. For instance, these individuals had a nearly 4-fold increase in a mutational signature molecule linked to tobacco smoking and a 76 per cent increase in another signature linked to ageing. 'What we see is that air pollution is associated with an increase in somatic mutations, including those that fall under known mutational signatures attributed to tobacco smoking and ageing,' said Marcos Díaz-Gay, co-author of the study. Scientists found that the more pollution someone was exposed to, the more mutations were found in their lung tumours, as well as greater signs of their cells undergoing accelerated ageing. Another environmental risk unravelled by the study was aristolochic acid, a known cancer-causing chemical found in some traditional Chinese and Ayurvedic herbal medicines. This chemical, extracted from plants of the birthwort family, was found linked to a signature mutation in lung tumours of never-smokers from Taiwan. Although ingestion of this plant chemical has been linked previously to bladder, gut, kidney, and liver cancers, the latest study is the first to report evidence that it may contribute to lung cancer. 'This raises new concerns about how traditional remedies might unintentionally raise cancer risk,' Dr Landi said. 'It also presents a public health opportunity for cancer prevention, particularly in Asia.' The study also found an intriguing new mutation signature which appears in the lung tumours of most never-smokers but is absent in smokers. 'We don't yet know what's driving it,' Dr Alexandrov said. 'This is something entirely different, and it opens up a whole new area of investigation.'
The Independent
03-07-2025
- Health
- The Independent
Air pollution and herbal medicines could be behind lung cancer in non-smokers, study finds
Air pollution and traditional herbal medicines could be major risk factors contributing to the development of lung cancer in people with no history of smoking, a groundbreaking new study has found. While smoking is a major risk factor for lung cancer, rates of the malignancy appear to be increasing among those who have never smoked, even with tobacco use declining globally. Previous studies have shown that lung cancer disproportionately affects non-smoking women, particularly those with Asian ancestry, and is more prevalent in East Asia than in Western nations. Now, a new study, published on Wednesday in the journal Nature, provides compelling evidence that air pollution and herbal medicines could be behind genetic mutations linked to the development of lung cancer in non-smokers. 'We are seeing this problematic trend that never-smokers are increasingly getting lung cancer, but we haven't understood why,' said Ludmil Alexandrov, an author of the study from the University of California San Diego. 'Our research shows that air pollution is strongly associated with the same types of DNA mutations we typically associate with smoking.' Most lung cancer prevalence studies haven't separated data of smokers from that of non-smokers, providing limited insights into potential causes in those patients. The latest study collected data from never-smokers worldwide and used genomics to find environmental factors likely behind these cancers. 'This is an urgent and growing global problem that we are working to understand regarding never-smokers,' said Maria Teresa Landi, co-author of the study from the US National Cancer Institute. While previous studies have shown a potential link between air pollution and lung cancer in never-smokers, the new research goes further by revealing a genomic link. In this comprehensive study, scientists analysed lung tumours from 871 never-smokers living in 28 regions with different levels of air pollution across Africa, Asia, Europe and North America. Researchers used genome sequencing methods to identify distinct patterns of genetic mutations which act like molecular fingerprints of past exposures. They then compared the genomic data with pollution estimates based on satellite and ground-level measurements of fine particulate matter. This helped them estimate long-term exposure of the patients to air pollution. The study found that never-smokers living in more polluted environments had significantly more mutations in their lung tumours, particularly the kinds which directly promote cancer development. Scientists also found more molecular signatures in this group, which are linked to cancer and serve as a record of all past exposures to mutation-causing environmental factors. For instance, these individuals had a nearly 4-fold increase in a mutational signature molecule linked to tobacco smoking and a 76 per cent increase in another signature linked to ageing. 'What we see is that air pollution is associated with an increase in somatic mutations, including those that fall under known mutational signatures attributed to tobacco smoking and ageing,' said Marcos Díaz-Gay, co-author of the study. Scientists found that the more pollution someone was exposed to, the more mutations were found in their lung tumours, as well as greater signs of their cells undergoing accelerated ageing. Another environmental risk unravelled by the study was aristolochic acid, a known cancer-causing chemical found in some traditional Chinese and Ayurvedic herbal medicines. This chemical, extracted from plants of the birthwort family, was found linked to a signature mutation in lung tumours of never-smokers from Taiwan. Although ingestion of this plant chemical has been linked previously to bladder, gut, kidney, and liver cancers, the latest study is the first to report evidence that it may contribute to lung cancer. 'This raises new concerns about how traditional remedies might unintentionally raise cancer risk,' Dr Landi said. 'It also presents a public health opportunity for cancer prevention, particularly in Asia.' The study also found an intriguing new mutation signature which appears in the lung tumours of most never-smokers but is absent in smokers. 'We don't yet know what's driving it,' Dr Alexandrov said. 'This is something entirely different, and it opens up a whole new area of investigation.'
The Hill
02-07-2025
- Health
- The Hill
Air pollution may be raising risk of lung cancer in ‘never-smokers': Study
Exposure to air pollution, other contaminants and traditional herbal medicines may be contributing to the development of lung cancer in people who have little or no history of smoking, a new study has found. Contact with these substances can be linked to the same genetic mutations that are associated with smoking and that promote lung cancer development, according to the study, published on Wednesday in Nature. 'We're seeing this problematic trend that never-smokers are increasingly getting lung cancer, but we haven't understood why,' co-senior author Ludmil Alexandrov, a professor of bioengineering and cellular and molecular medicine at the University of California San Diego, said in a statement. Even as tobacco use has plunged in many parts of the world, lung cancer in individuals who have never smoked is proportionally on the rise, the researchers noted. Those effects, they noted, are particularly pronounced in women of Asian ancestry and are more prevalent in East Asia than in Western nations. Although previous research has identified an epidemiological link between air pollution and link cancer in never-smokers, the current study authors went a step further in establishing a genomic reason behind this phenomenon. To do so, they analyzed lung tumors from 871 never-smokers in 28 regions with varying levels of air pollution, across Africa, Asia, Europe and Norther America. Utilizing whole-genome sequencing, the scientists identified specific patterns of DNA mutations — or 'mutational signatures' — that serves as molecular fingerprints for past exposures responsible for changes in DNA. After combining their genomic data with satellite and ground-level pollution measurements of fine particulate matter, they were able to estimate the long-term exposure levels of their participants. The scientists found that never-smokers living in more polluted environments developed much more mutations in their lung tumors — especially the types of mutations that directly drive cancer development. These individuals also showed more mutational signatures linked to cancer, per the study. This cohort of participants demonstrated a 3.9-fold surge in mutational signature that is typically linked to tobacco smoking. Meanwhile, the scientists also determined that the more air pollution a person endured, the more tumors were found in their lungs. These tumors also had shorter telomeres —the protective caps on the ends of chromosomes — a warning sign of accelerated cellular aging. Although the researchers identified this genetic link between air pollution exposures and lung cancer, they did not find a strong correlation when it came to secondhand smoke. Exposure to secondhand smoke is a known cancer risk, but its mutational impacts were far less acute than those identified with air pollution — generating just a small rise in such changes, according to the study. 'If there is a mutagenic effect of secondhand smoke, it may be too weak for our current tools to detect,' co-first author Tongwu Zhang, a biostatistician at the National Institutes of Health's National Cancer Institute, said in a statement. In addition to focusing in on air pollution, the researchers also examined the effects of aristolochic acid, a carcinogen present in certain traditional Chinese herbal medicines. They flagged a specific mutational signature associated with the acid that was present almost exclusively in lung cancer cases of Taiwanese never-smokers. While aristolochic acid and previously been linked to bladder, gastrointestinal, kidney and liver cancers from ingestion, the researchers said they suspect that the inhalation of the substance could be connected to the lung cancer cases — though they recognized a need for further research. 'This raises new concerns about how traditional remedies might unintentionally raise cancer risk,' co-senior author Maria Teresa Landi, an epidemiologist at the National Cancer Institute, said in a statement. 'It also presents a public health opportunity for cancer prevention — particularly in Asia.'
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.
