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Toxins, tech and tumors: Is modern life fueling the rise of cancer in millennials?

News Feed
Tuesday, September 23, 2025

ST. LOUIS — Gary Patti leaned in to study the rows of plastic tanks, where dozens of translucent zebrafish flickered through chemically treated water. Each tank contained a different substance — some notorious, others less well understood — all known or suspected carcinogens.Patti’s team is watching them closely, tracking which fish develop tumors, to try to find clues to one of the most unsettling medical puzzles of our time: Why are so many young people getting cancer?The trend began with younger members of Generation X but is now most visible among millennials, who are being diagnosed in their 20s, 30s, and early 40s — decades earlier than past generations. Medications taken during pregnancy, the spread of ultra-processed foods, disruptions to circadian rhythms — caused by late-night work, global travel and omnipresent screens — and the proliferation of synthetic chemicals are all under scrutiny.Young women are more affected than men. From ages 15 through 49, women have a cancer rate that is 83 percent higher than men in the same age range.The rise in early-onset cancers has drawn a growing number of scientists into a shared investigation: not into the inherited traits that remain largely unchanged as a cause of cancer across generations, but into the ways modern life might be rewriting the body’s cellular fate. The new research direction examines the “exposome” — the full range of environmental exposures a person experiences throughout his or her life, even before birth — and how those exposures interact with biology.Many researchers are focusing on a window that opened in the 1960s and ’70s and accelerated in the ’80s and beyond, when a wave of new exposures entered daily life.Certain medications taken during pregnancy may disrupt fetal development or programming of gene activity, potentially increasing susceptibility to early-onset cancers.Exposure to environmental chemicals — including those in microplastics that accumulate in tissues after being ingested or inhaled — can increase the risk of hormonal imbalances, genetic mutations, inflammation and other effects that contribute to early cancers.A diet that contains large quantities of highly processed food can influence cancer risk by promoting inflammation, obesity and metabolic changes that may trigger tumorigenesis.Disruption of circadian rhythms may impair DNA repair mechanisms and hormone, metabolic and immune regulation, heightening the risk of early-onset malignancies.The research is sprawling and interdisciplinary, but it is beginning to align around a provocative hypothesis: Shifts in everyday exposures may be accelerating biological aging, priming the body for disease earlier than expected.“We’ve changed what we’re exposed to considerably in the past few decades,” said Patti, a professor of chemistry, genetics and medicine at the Washington University School of Medicine in St. Louis.The sheer complexity of modern life makes it difficult to pinpoint specific culprits. But advances in rapid, high-volume chemical screening, machine learning, and vast population datasets have made it possible to look with unparalleled depth and detail into the human body and the world around it. These methods test thousands of variables at once, revealing some never-before-seen patterns.Gary Patti, a biochemist at Washington University in St. Louis, is leading efforts to decode complex data about people’s past chemical exposures. (Photo by Michael Thomas/For The Washington Post)Last year, researchers released findings from a 150,000-person study at the annual American Association for Cancer Research meeting that took the cancer community by surprise. They found that millennials — born between 1981 and 1996 — appear to be aging biologically faster than previous generations, based on biomarkers in blood that indicate the health of various organs. That acceleration was associated with a significantly increased risk — up to 42 percent — for certain cancers, especially those of the lung, gastrointestinal tract and uterus.Much of the work in this area is in its early stages and has not proved a direct cause and effect in humans. The evidence comes from epidemiological studies, which look at patterns of disease in large populations; observational studies, which track people’s behaviors and exposures without intervening; and animal models which are sometimes, but not always, good proxies for people. Such research is difficult to interpret and especially prone to overstatement or misreading of the data.John Ioannidis, a professor of medicine, epidemiology and population health at Stanford University, said research that searches for correlations across large datasets is highly susceptible to producing spurious results. While he believes there is strong and growing data that there are a lot of harmful exposures in today’s environment, he emphasized, “We should not panic and think everything new we live with is toxic.”Identifying the forces behind the rise in cancer among young people is only the first step. Confronting them and developing treatment may be an even more complex task. Microplastics drift through our bloodstreams; synthetic chemicals line our homes, our food, our clothes; and modern medicine depends on many of the same substances that may be contributing to the problem.Researcher say the surge in cancer cases among young adults reflects a deeper trend human health: A number of major diseases, from heart disease to Alzheimer’s disease, aren’t just being detected earlier — they’re actually starting earlier in life.“This is not just about cancer,” said Yin Cao, an associate professor of surgery at the Washington University School of Medicine in St. Louis whose team led the accelerated aging study. “This is a universal problem across different diseases.”Pregnancy iconMaternal medicationsModern medicine has profoundly altered the experience of pregnancy. Women giving birth in the second half of the 20th century were treated with drugs not as an exception, but a new standard. Antidepressants, anti-nausea medications, antibiotics, hormone treatments — even in combinations, sometimes all in one trimester — heralded a new normal of active pregnancy management.At the time, these developments were seen as progress; the pregnancy was safer and more comfortable thanks to science. However, as researchers revisit this era with new methods and by examining how events unfolded over an extended period — and with the discovery of the link between morning sickness drug thalidomide and birth defects in the 1960s — a more complicated story has emerged.What if a drug’s real risk may not be apparent in the days or weeks after birth, but only show years — or possibly decades — later?Caitlin Murphy, a professor and cancer epidemiologist at the University of Chicago, found herself wrestling with exactly this question. While combing through epidemiological data, she noticed a curious trend. The rise in cancer diagnoses tracked with birth year.But rather than a steady increase across the board, cancer rates appeared to spike among millennials. The pattern, Murphy realized, was about a birth cohort, a group of people born during the same period.Caitlin Murphy uncovered a link between an anti-nausea drug used during pregnancy and early-onset cancers. (Courtesy of Caitlin Murphy)“The rates weren’t just increasing with age — they varied dramatically by generation,” she explained.At 37, Murphy had personal reasons to care. Her mother was diagnosed and died of cancer in her 40s. Now, nearing that age herself, Murphy began to wonder whether the mystery of rising early-onset cancers might begin not in adolescence, but in gestation.To find out, she turned to one of the longest-running maternal health studies in the United States — a cohort in Northern California that began collecting blood samples from pregnant women in 1959. The mid-century period, Murphy knew, was a golden age of medical intervention in pregnancy: a time when hormonal treatments, sedatives and experimental drugs were widely prescribed to expectant mothers, often with little long-term follow-up.By linking these prenatal medical records to statewide cancer registries, Murphy determined that children whose mothers had taken bendectin, an anti-nausea drug, during pregnancy were 3.6 times more likely to develop colon cancer as adults, when all other factors were taken into consideration. Even more startling was that children of women who received a different medication to prevent miscarriage, hydroxyprogesterone caproate, had more than double the overall lifetime cancer risk. In this group, about 65 percent of cancers occurred before the age of 50.Bendectin was voluntarily withdrawn from the market in 1983 amid concerns about birth defects. Follow up testing found no link with birth defects. The Food and Drug Administration withdrew its approval for a brand name and generic hydroxyprogesterone caproate in 2023 for preventing preterm birth after a large clinical trial failed to prove the drug works.Diet iconDietBy the 1980s and ’90s, a new kind of diet had become the norm.Shelf-stable snacks, frozen entrées, sugary cereals and reconstituted meats filled lunch boxes, cupboards and grocery store aisles. It was a drastic change in the food habits from generations past, which had grown up with diets made up mostly of meals cooked at home with whole foods.Today, ultra-processed foods account for more than half of the total daily calorie intake in the United States, among other countries. Designed for flavor, convenience, and shelf stability, they have been correlated with rising rates of obesity and metabolic disease — and perhaps a rise in cancer in young adults.A 2023 study published in the BMJ found that heavy consumption of ultra-processed foods was associated with significantly elevated risks of developing several cancers, including colorectal and breast cancer — two of the fastest-rising malignancies in people under 50.According to the Post analysis of the latest data, breast, thyroid, colon-rectum, skin and cancers of the testes are the most common diagnoses for young adults. Young people are more likely to suffer late diagnoses of some of the most common cancers.Types of cancerAndrew Chan, a gastroenterologist at Massachusetts General Hospital and professor of medicine at Harvard Medical School, is co-lead of a global research initiative launched in 2024 to investigate the surge in colon cancer among young adults. In May, his team presented early findings suggesting a troubling link. Individuals under 50 who consumed the largest quantities of ultra-processed foods faced a 1.5-fold increased risk of developing early-onset colon tumors.Researchers Etienne Nzabarushimana (l) and Andrew Chan (c) from Massachusetts General Hospital and Yin Cao (r) from the Washington University in St. Louis are part of a group of scientists from the United States, U.K., France, Mexico, and India who have launched a global effort to understand the surprising rise of colon cancer in young adults. (Courtesy Andrew Chan) The association, Chan emphasized, isn’t simply about weight gain.“Ultra-processed foods appear to have independent metabolic effects that could have negative consequences on human health,” Chan said.Scientists are examining a variety of ways these products could possibly cause cancer: chronic inflammation caused by additives, the disruption of gut microbiota by emulsifiers, carcinogenic compounds formed during high-heat cooking and changes to hormones from excess sugar and carbohydrates. Even packaging might play a role, because leaching chemicals, particularly when heated, from plastics may disrupt the balance of hormones in the body.As part of his research, Chan is preparing a clinical trial to test whether the new generation of diabetes and weight loss drugs such as Zepbound can slow molecular changes associated with cancer younger adults. If industrial food has affected a generation’s health, he wonders, can that trajectory be altered?Circadian rhythmNearly every organism on Earth, from bacteria to humans, runs on a biological rhythm shaped by the rotation of the planet. This internal clock — the circadian system — regulates everything from hormone release to cell repair, syncing the body to the 24-hour cycle of light and dark.But over recent decades, the explosion of artificial light, erratic work schedules and 24/7 digital connectivity has fundamentally altered when and how we sleep, eat and rest. As a result, researchers, many of whom have been funded by the National Institute for General Medical Sciences, say the biological processes that rely on the rising and setting sun — like immune regulation, endocrine control and metabolic functions — may unravel.Melatonin, a hormone produced in darkness, plays a crucial role in this system. But in today’s glowing, sleepless world, melatonin production is regularly disrupted.Research has linked chronic circadian misalignment to higher risks of breast, colorectal, lung, liver and pancreatic cancers, all increasingly diagnosed in younger populations. And in 2007, the International Agency for Research on Cancer declared shift work that disturbs circadian rhythms a probable human carcinogen.Katja Lamia, a professor of molecular and cellular biology at Scripps Research, found that mice with lung cancer exposed to conditions that simulate chronic jet lag developed 68 percent more tumors than those that got more regular sleep.Katja Lamia, a professor of molecular and cellular biology at Scripps Research, studies the relationship between circadian clocks and DNA damage which can lead to cancers. (Brendan Cleak)At the University of California at Irvine, Selma Masri found similar effects related to colorectal cancer. Using animal models to mimic the impact of shift work, jet lag and constant light exposure on humans, she found that circadian disruption alters the gut microbiome and intestinal barrier function, potentially making it easier for cancerous cells to spread.“Our bodies need those dark periods for many aspects of homeostasis,” Masri, an associate professor of biological chemistry at the UC-Irvine School of Medicine, explained.Chemicals and microplasticsPatti is a biochemist by training, but his vigilance doesn’t stop at the lab.Married with two young children, his scientific knowledge has deeply shaped his family’s lifestyle. At home, he practices what he calls “exposure remediation” — scrutinizing ingredients on shampoo bottles for questionable dyes, scanning cleaning products for chemicals known to disrupt hormones, and avoiding anything scented or labeled “antibacterial” to reduce exposure to substances that might weaken the body’s natural defenses against disease.Chemical and plastic exposure today is diffuse, ambient and inescapable, unlike legacy toxins such as asbestos or lead, which tended to me more occupational or localized.“There’s still so much we don’t understand about how these exposures interact with our bodies,” he said. “But we do know that small changes, especially early on, can have lasting effects.”The growth in chemical exposure has grown in tandem with the explosion of microplastics. By the 1980s and ’90s, entire generations chewed on plastic toys, ate food wrapped in cling film, and drank from microwaved containers. Microplastics have now been found in the placenta, the lungs and even the brain and heart.These fragments act as sponges for environmental toxins; laboratory studies demonstrate that microplastics can damage DNA, interfere with cell division and promote chronic inflammation, a well-known mechanism in carcinogenesis. In animal models, microplastic exposure has been linked to colon and lung cancer and immune system dysregulation. An analysis of peer-reviewed studies published in December 2024 and led by University of Sydney researcher Nicholas Chartres, scientific lead of the Center to End Corporate Harm, University of California at San Francisco, found repeated evidence linking microplastic exposure to mechanisms indicative of cancer across multiple systems — digestive and respiratory.University of Sydney researcher Nicholas Chartres found repeated evidence linking microplastic exposure to mechanisms indicative of cancer across the digestive and respiratory systems. (Fiona Wolf/The University of Sydney)The Centers for Disease Control and Prevention has estimated that 97 percent of Americans have some level of toxic “forever chemicals” — a group of synthetic compounds often found in plastics with negative health effects that persist in the environment and in the human body — in their blood.It’s this hidden complexity that drives Patti’s work.His team is focused on metabolomics — the vast, largely unmapped study of the small molecules coursing through the human body. Using high-resolution mass spectrometry and custom-built computational tools, Patti’s lab has developed a system capable of scanning a single blood sample for tens of thousands of chemicals at once.At Washington University in St. Louis, the Patti Lab is analyzing human samples, tracing past chemical exposures to help uncover what’s driving the rise in colon cancer among young people. (Michael Thomas/For The Washington Post)Traditional toxicology has been reactive, testing chemicals one by one, often after problems emerge. Patti’s approach flips that model — scanning everything first and asking questions later. The goal is to find chemical signatures that appear more often in people diagnosed with early-onset cancers than in those without.“We’re just now beginning to understand the full chemical complexity of modern life,” he said. There are estimated to be more than 100,000 synthetic chemicals on the market. Their global production has almost doubled since 2000.Only a small fraction of these have been studied for links to cancer: The International Agency for Research on Cancer (IARC) puts this number at about 4 percent. But among those examined, many have been shown to have some links to the disease. A 2024 study in Environmental Health Perspectives, for example, identified 921 chemicals that could promote the development of breast cancer.Patti’s zebrafish research explores how diet and chemical exposure interact in cancer development. Beneath the glow of the lab’s cool lights, tiny fish dart through their tanks — some fed a standard, unremarkable diet, others given tightly controlled meals. The study is still ongoing, but early data is starting to raise questions about the role of artificial sugars.He hopes his lab’s work may one day provide access to tests that provide snapshots of a person’s environmental history written directly into the blood, offering clues not just about cancer’s origins, but about how we might finally begin to prevent it.“The data,” Patti added, “is already in us.”

Studies suggest modern life may be fueling the rise of cancer in younger adults, with factors like ultra-processed foods and chemicals under scrutiny.

ST. LOUIS — Gary Patti leaned in to study the rows of plastic tanks, where dozens of translucent zebrafish flickered through chemically treated water. Each tank contained a different substance — some notorious, others less well understood — all known or suspected carcinogens.

Patti’s team is watching them closely, tracking which fish develop tumors, to try to find clues to one of the most unsettling medical puzzles of our time: Why are so many young people getting cancer?

The trend began with younger members of Generation X but is now most visible among millennials, who are being diagnosed in their 20s, 30s, and early 40s — decades earlier than past generations. Medications taken during pregnancy, the spread of ultra-processed foods, disruptions to circadian rhythms — caused by late-night work, global travel and omnipresent screens — and the proliferation of synthetic chemicals are all under scrutiny.

Young women are more affected than men. From ages 15 through 49, women have a cancer rate that is 83 percent higher than men in the same age range.

The rise in early-onset cancers has drawn a growing number of scientists into a shared investigation: not into the inherited traits that remain largely unchanged as a cause of cancer across generations, but into the ways modern life might be rewriting the body’s cellular fate. The new research direction examines the “exposome” — the full range of environmental exposures a person experiences throughout his or her life, even before birth — and how those exposures interact with biology.

Many researchers are focusing on a window that opened in the 1960s and ’70s and accelerated in the ’80s and beyond, when a wave of new exposures entered daily life.

Certain medications taken during pregnancy may disrupt fetal development or programming of gene activity, potentially increasing susceptibility to early-onset cancers.

Exposure to environmental chemicals — including those in microplastics that accumulate in tissues after being ingested or inhaled — can increase the risk of hormonal imbalances, genetic mutations, inflammation and other effects that contribute to early cancers.

A diet that contains large quantities of highly processed food can influence cancer risk by promoting inflammation, obesity and metabolic changes that may trigger tumorigenesis.

Disruption of circadian rhythms may impair DNA repair mechanisms and hormone, metabolic and immune regulation, heightening the risk of early-onset malignancies.

The research is sprawling and interdisciplinary, but it is beginning to align around a provocative hypothesis: Shifts in everyday exposures may be accelerating biological aging, priming the body for disease earlier than expected.

“We’ve changed what we’re exposed to considerably in the past few decades,” said Patti, a professor of chemistry, genetics and medicine at the Washington University School of Medicine in St. Louis.

The sheer complexity of modern life makes it difficult to pinpoint specific culprits. But advances in rapid, high-volume chemical screening, machine learning, and vast population datasets have made it possible to look with unparalleled depth and detail into the human body and the world around it. These methods test thousands of variables at once, revealing some never-before-seen patterns.

Gary Patti, a biochemist at Washington University in St. Louis, is leading efforts to decode complex data about people’s past chemical exposures. (Photo by Michael Thomas/For The Washington Post)

Last year, researchers released findings from a 150,000-person study at the annual American Association for Cancer Research meeting that took the cancer community by surprise. They found that millennials — born between 1981 and 1996 — appear to be aging biologically faster than previous generations, based on biomarkers in blood that indicate the health of various organs. That acceleration was associated with a significantly increased risk — up to 42 percent — for certain cancers, especially those of the lung, gastrointestinal tract and uterus.

Much of the work in this area is in its early stages and has not proved a direct cause and effect in humans. The evidence comes from epidemiological studies, which look at patterns of disease in large populations; observational studies, which track people’s behaviors and exposures without intervening; and animal models which are sometimes, but not always, good proxies for people. Such research is difficult to interpret and especially prone to overstatement or misreading of the data.

John Ioannidis, a professor of medicine, epidemiology and population health at Stanford University, said research that searches for correlations across large datasets is highly susceptible to producing spurious results. While he believes there is strong and growing data that there are a lot of harmful exposures in today’s environment, he emphasized, “We should not panic and think everything new we live with is toxic.”

Identifying the forces behind the rise in cancer among young people is only the first step. Confronting them and developing treatment may be an even more complex task. Microplastics drift through our bloodstreams; synthetic chemicals line our homes, our food, our clothes; and modern medicine depends on many of the same substances that may be contributing to the problem.

Researcher say the surge in cancer cases among young adults reflects a deeper trend human health: A number of major diseases, from heart disease to Alzheimer’s disease, aren’t just being detected earlier — they’re actually starting earlier in life.

“This is not just about cancer,” said Yin Cao, an associate professor of surgery at the Washington University School of Medicine in St. Louis whose team led the accelerated aging study. “This is a universal problem across different diseases.”

Pregnancy icon

Maternal medications

Modern medicine has profoundly altered the experience of pregnancy. Women giving birth in the second half of the 20th century were treated with drugs not as an exception, but a new standard. Antidepressants, anti-nausea medications, antibiotics, hormone treatments — even in combinations, sometimes all in one trimester — heralded a new normal of active pregnancy management.

At the time, these developments were seen as progress; the pregnancy was safer and more comfortable thanks to science. However, as researchers revisit this era with new methods and by examining how events unfolded over an extended period — and with the discovery of the link between morning sickness drug thalidomide and birth defects in the 1960s — a more complicated story has emerged.

What if a drug’s real risk may not be apparent in the days or weeks after birth, but only show years — or possibly decades — later?

Caitlin Murphy, a professor and cancer epidemiologist at the University of Chicago, found herself wrestling with exactly this question. While combing through epidemiological data, she noticed a curious trend. The rise in cancer diagnoses tracked with birth year.

But rather than a steady increase across the board, cancer rates appeared to spike among millennials. The pattern, Murphy realized, was about a birth cohort, a group of people born during the same period.

Caitlin Murphy uncovered a link between an anti-nausea drug used during pregnancy and early-onset cancers. (Courtesy of Caitlin Murphy)

“The rates weren’t just increasing with age — they varied dramatically by generation,” she explained.

At 37, Murphy had personal reasons to care. Her mother was diagnosed and died of cancer in her 40s. Now, nearing that age herself, Murphy began to wonder whether the mystery of rising early-onset cancers might begin not in adolescence, but in gestation.

To find out, she turned to one of the longest-running maternal health studies in the United States — a cohort in Northern California that began collecting blood samples from pregnant women in 1959. The mid-century period, Murphy knew, was a golden age of medical intervention in pregnancy: a time when hormonal treatments, sedatives and experimental drugs were widely prescribed to expectant mothers, often with little long-term follow-up.

By linking these prenatal medical records to statewide cancer registries, Murphy determined that children whose mothers had taken bendectin, an anti-nausea drug, during pregnancy were 3.6 times more likely to develop colon cancer as adults, when all other factors were taken into consideration. Even more startling was that children of women who received a different medication to prevent miscarriage, hydroxyprogesterone caproate, had more than double the overall lifetime cancer risk. In this group, about 65 percent of cancers occurred before the age of 50.

Bendectin was voluntarily withdrawn from the market in 1983 amid concerns about birth defects. Follow up testing found no link with birth defects. The Food and Drug Administration withdrew its approval for a brand name and generic hydroxyprogesterone caproate in 2023 for preventing preterm birth after a large clinical trial failed to prove the drug works.

Diet icon

Diet

By the 1980s and ’90s, a new kind of diet had become the norm.

Shelf-stable snacks, frozen entrées, sugary cereals and reconstituted meats filled lunch boxes, cupboards and grocery store aisles. It was a drastic change in the food habits from generations past, which had grown up with diets made up mostly of meals cooked at home with whole foods.

Today, ultra-processed foods account for more than half of the total daily calorie intake in the United States, among other countries. Designed for flavor, convenience, and shelf stability, they have been correlated with rising rates of obesity and metabolic disease — and perhaps a rise in cancer in young adults.

A 2023 study published in the BMJ found that heavy consumption of ultra-processed foods was associated with significantly elevated risks of developing several cancers, including colorectal and breast cancer — two of the fastest-rising malignancies in people under 50.

According to the Post analysis of the latest data, breast, thyroid, colon-rectum, skin and cancers of the testes are the most common diagnoses for young adults. Young people are more likely to suffer late diagnoses of some of the most common cancers.

Types of cancer

Andrew Chan, a gastroenterologist at Massachusetts General Hospital and professor of medicine at Harvard Medical School, is co-lead of a global research initiative launched in 2024 to investigate the surge in colon cancer among young adults. In May, his team presented early findings suggesting a troubling link. Individuals under 50 who consumed the largest quantities of ultra-processed foods faced a 1.5-fold increased risk of developing early-onset colon tumors.

Researchers Etienne Nzabarushimana (l) and Andrew Chan (c) from Massachusetts General Hospital and Yin Cao (r) from the Washington University in St. Louis are part of a group of scientists from the United States, U.K., France, Mexico, and India who have launched a global effort to understand the surprising rise of colon cancer in young adults. (Courtesy Andrew Chan)

The association, Chan emphasized, isn’t simply about weight gain.

“Ultra-processed foods appear to have independent metabolic effects that could have negative consequences on human health,” Chan said.

Scientists are examining a variety of ways these products could possibly cause cancer: chronic inflammation caused by additives, the disruption of gut microbiota by emulsifiers, carcinogenic compounds formed during high-heat cooking and changes to hormones from excess sugar and carbohydrates. Even packaging might play a role, because leaching chemicals, particularly when heated, from plastics may disrupt the balance of hormones in the body.

As part of his research, Chan is preparing a clinical trial to test whether the new generation of diabetes and weight loss drugs such as Zepbound can slow molecular changes associated with cancer younger adults. If industrial food has affected a generation’s health, he wonders, can that trajectory be altered?

Circadian rhythm

Nearly every organism on Earth, from bacteria to humans, runs on a biological rhythm shaped by the rotation of the planet. This internal clock — the circadian system — regulates everything from hormone release to cell repair, syncing the body to the 24-hour cycle of light and dark.

But over recent decades, the explosion of artificial light, erratic work schedules and 24/7 digital connectivity has fundamentally altered when and how we sleep, eat and rest. As a result, researchers, many of whom have been funded by the National Institute for General Medical Sciences, say the biological processes that rely on the rising and setting sun — like immune regulation, endocrine control and metabolic functions — may unravel.

Melatonin, a hormone produced in darkness, plays a crucial role in this system. But in today’s glowing, sleepless world, melatonin production is regularly disrupted.

Research has linked chronic circadian misalignment to higher risks of breast, colorectal, lung, liver and pancreatic cancers, all increasingly diagnosed in younger populations. And in 2007, the International Agency for Research on Cancer declared shift work that disturbs circadian rhythms a probable human carcinogen.

Katja Lamia, a professor of molecular and cellular biology at Scripps Research, found that mice with lung cancer exposed to conditions that simulate chronic jet lag developed 68 percent more tumors than those that got more regular sleep.

Katja Lamia, a professor of molecular and cellular biology at Scripps Research, studies the relationship between circadian clocks and DNA damage which can lead to cancers. (Brendan Cleak)

At the University of California at Irvine, Selma Masri found similar effects related to colorectal cancer. Using animal models to mimic the impact of shift work, jet lag and constant light exposure on humans, she found that circadian disruption alters the gut microbiome and intestinal barrier function, potentially making it easier for cancerous cells to spread.

“Our bodies need those dark periods for many aspects of homeostasis,” Masri, an associate professor of biological chemistry at the UC-Irvine School of Medicine, explained.

Chemicals and microplastics

Patti is a biochemist by training, but his vigilance doesn’t stop at the lab.

Married with two young children, his scientific knowledge has deeply shaped his family’s lifestyle. At home, he practices what he calls “exposure remediation” — scrutinizing ingredients on shampoo bottles for questionable dyes, scanning cleaning products for chemicals known to disrupt hormones, and avoiding anything scented or labeled “antibacterial” to reduce exposure to substances that might weaken the body’s natural defenses against disease.

Chemical and plastic exposure today is diffuse, ambient and inescapable, unlike legacy toxins such as asbestos or lead, which tended to me more occupational or localized.

“There’s still so much we don’t understand about how these exposures interact with our bodies,” he said. “But we do know that small changes, especially early on, can have lasting effects.”

The growth in chemical exposure has grown in tandem with the explosion of microplastics. By the 1980s and ’90s, entire generations chewed on plastic toys, ate food wrapped in cling film, and drank from microwaved containers. Microplastics have now been found in the placenta, the lungs and even the brain and heart.

These fragments act as sponges for environmental toxins; laboratory studies demonstrate that microplastics can damage DNA, interfere with cell division and promote chronic inflammation, a well-known mechanism in carcinogenesis. In animal models, microplastic exposure has been linked to colon and lung cancer and immune system dysregulation. An analysis of peer-reviewed studies published in December 2024 and led by University of Sydney researcher Nicholas Chartres, scientific lead of the Center to End Corporate Harm, University of California at San Francisco, found repeated evidence linking microplastic exposure to mechanisms indicative of cancer across multiple systems — digestive and respiratory.

University of Sydney researcher Nicholas Chartres found repeated evidence linking microplastic exposure to mechanisms indicative of cancer across the digestive and respiratory systems. (Fiona Wolf/The University of Sydney)

The Centers for Disease Control and Prevention has estimated that 97 percent of Americans have some level of toxic “forever chemicals” — a group of synthetic compounds often found in plastics with negative health effects that persist in the environment and in the human body — in their blood.

It’s this hidden complexity that drives Patti’s work.

His team is focused on metabolomics — the vast, largely unmapped study of the small molecules coursing through the human body. Using high-resolution mass spectrometry and custom-built computational tools, Patti’s lab has developed a system capable of scanning a single blood sample for tens of thousands of chemicals at once.

At Washington University in St. Louis, the Patti Lab is analyzing human samples, tracing past chemical exposures to help uncover what’s driving the rise in colon cancer among young people. (Michael Thomas/For The Washington Post)

Traditional toxicology has been reactive, testing chemicals one by one, often after problems emerge. Patti’s approach flips that model — scanning everything first and asking questions later. The goal is to find chemical signatures that appear more often in people diagnosed with early-onset cancers than in those without.

“We’re just now beginning to understand the full chemical complexity of modern life,” he said. There are estimated to be more than 100,000 synthetic chemicals on the market. Their global production has almost doubled since 2000.

Only a small fraction of these have been studied for links to cancer: The International Agency for Research on Cancer (IARC) puts this number at about 4 percent. But among those examined, many have been shown to have some links to the disease. A 2024 study in Environmental Health Perspectives, for example, identified 921 chemicals that could promote the development of breast cancer.

Patti’s zebrafish research explores how diet and chemical exposure interact in cancer development. Beneath the glow of the lab’s cool lights, tiny fish dart through their tanks — some fed a standard, unremarkable diet, others given tightly controlled meals. The study is still ongoing, but early data is starting to raise questions about the role of artificial sugars.

He hopes his lab’s work may one day provide access to tests that provide snapshots of a person’s environmental history written directly into the blood, offering clues not just about cancer’s origins, but about how we might finally begin to prevent it.

“The data,” Patti added, “is already in us.”

Read the full story here.
Photos courtesy of

James Watson, Co-Discoverer of DNA's Double Helix, Dead at 97

(Reuters) -James D. Watson, the brilliant but controversial American biologist whose 1953 discovery of the structure of DNA, the molecule of...

(Reuters) -James D. Watson, the brilliant but controversial American biologist whose 1953 discovery of the structure of DNA, the molecule of heredity, ushered in the age of genetics and provided the foundation for the biotechnology revolution of the late 20th century, has died at the age of 97.His death was confirmed by Cold Spring Harbor Laboratory on Long Island, where he worked for many years. The New York Times reported that Watson died this week at a hospice on Long Island.In his later years, Watson's reputation was tarnished by comments on genetics and race that led him to be ostracized by the scientific establishment.Even as a younger man, he was known as much for his writing and for his enfant-terrible persona - including his willingness to use another scientist's data to advance his own career - as for his science.His 1968 memoir, "The Double Helix," was a racy, take-no-prisoners account of how he and British physicist Francis Crick were first to determine the three-dimensional shape of DNA. The achievement won the duo a share of the 1962 Nobel Prize in medicine and eventually would lead to genetic engineering, gene therapy and other DNA-based medicine and technology.Crick complained that the book "grossly invaded my privacy" and another colleague, Maurice Wilkins, objected to what he called a "distorted and unfavorable image of scientists" as ambitious schemers willing to deceive colleagues and competitors in order to make a discovery.In addition, Watson and Crick, who did their research at Cambridge University in England, were widely criticized for using raw data collected by X-ray crystallographer Rosalind Franklin to construct their model of DNA - as two intertwined staircases - without fully acknowledging her contribution. As Watson put it in "Double Helix," scientific research feels "the contradictory pulls of ambition and the sense of fair play."In 2007, Watson again caused widespread anger when he told the Times of London that he believed testing indicated the intelligence of Africans was "not really ... the same as ours."Accused of promoting long-discredited racist theories, he was shortly afterwards forced to retire from his post as chancellor of New York's Cold Spring Harbor Laboratory (CSHL). Although he later apologized, he made similar comments in a 2019 documentary, calling different racial attainment on IQ tests - attributed by most scientists to environmental factors - "genetic."James Dewey Watson was born in Chicago on April 6, 1928, and graduated from the University of Chicago in 1947 with a zoology degree. He received his doctorate from Indiana University, where he focused on genetics. In 1951, he joined Cambridge's Cavendish Lab, where he met Crick and began the quest for the structural chemistry of DNA.Just waiting to be found, the double helix opened the doors to the genetics revolution. In the structure Crick and Watson proposed, the steps of the winding staircase were made of pairs of chemicals called nucleotides or bases. As they noted at the end of their 1953 paper, "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material."That sentence, often called the greatest understatement in the history of biology, meant that the base-and-helix structure provided the mechanism by which genetic information can be precisely copied from one generation to the next. That understanding led to the discovery of genetic engineering and numerous other DNA techniques.Watson and Crick went their separate ways after their DNA research. Watson was only 25 years old then and while he never made another scientific discovery approaching the significance of the double helix, he remained a scientific force."He had to figure out what to do with his life after achieving what he did at such a young age," biologist Mark Ptashne, who met Watson in the 1960s and remained a friend, told Reuters in a 2012 interview. "He figured out how to do things that played to his strength."That strength was playing "the tough Irishman," as Ptashne put it, to become one of the leaders of the U.S. leap to the forefront of molecular biology. Watson joined the biology department at Harvard University in 1956."The existing biology department felt that molecular biology was just a flash in the pan," Harvard biochemist Guido Guidotti related. But when Watson arrived, Guidotti said he immediately told everyone in the biology department – scientists whose research focused on whole organisms and populations, not cells and molecules – "that they were wasting their time and should retire."That earned Watson the decades-long enmity of some of those traditional biologists, but he also attracted young scientists and graduate students who went on to forge the genetics revolution.In 1968 Watson took his institution-building drive to CSHL on Long Island, splitting his time between CSHL and Harvard for eight years. The lab at the time was "just a mosquito-infested backwater," said Ptashne. As director, "Jim turned it into a vibrant, world-class institution."In 1990, Watson was named to lead the Human Genome Project, whose goal was to determine the order of the 3 billion chemical units that constitute humans' full complement of DNA. When the National Institutes of Health, which funded the project, decided to seek patents on some DNA sequences, Watson attacked the NIH director and resigned, arguing that genome knowledge should remain in the public domain.In 2007 he became the second person in the world to have his full genome sequenced. He made the sequence publicly available, arguing that concerns about "genetic privacy" were overwrought but made an exception by saying he did not want to know if he had a gene associated with an increased risk of Alzheimer's disease. Watson did have a gene associated with novelty-seeking.His proudest accomplishment, Watson told an interviewer for Discover magazine in 2003, was not discovering the double helix - which "was going to be found in the next year or two" anyway - but his books."My heroes were never scientists," he said. "They were Graham Greene and Christopher Isherwood - you know, good writers."Watson cherished the bad-boy image he presented to the world in "Double Helix," friends said, and he emphasized it in his 2007 book, "Avoid Boring People."Married with two sons, he often disparaged women in public statements and boasted of chasing what he called "popsies." But he personally encouraged many female scientists, including biologist Nancy Hopkins of the Massachusetts Institute of Technology."I certainly couldn't have had a career in science without his support, I believe," said Hopkins, long outspoken about anti-woman bias in science. "Jim was hugely supportive of me and other women. It's an odd thing to understand."(Editing by Bill Trott and Rosalba O'Brien)Copyright 2025 Thomson Reuters.Photos You Should See – Oct. 2025

How dry cleaning might raise the risk of cancer, and what to do about it

A new study found links between a toxic dry cleaning chemical and liver cancer. Trump officials are reconsidering an EPA plan to phase it out.

Environmental and health advocates have long sought to curb dangerous chemicals used in dry cleaning. Now a new study adds to the evidence of harms, linking a common dry cleaning chemical to liver disease and cancer.Here’s what you need to know about the risks.How dry cleaning worksDespite the name, clothes don’t stay “dry” when dry-cleaned. Instead, garments are loaded into drums and soaked in chemicals that dissolve stains.Before modern cleaning systems were developed, workers would manually move solvent-soaked garments from washer to dryer, creating a direct exposure route and increasing the chances of environmental contamination. Today, cleaners wash and dry everything in the same drum. Clothes are then pressed or steamed.What are the health risks?One of the most widely used dry cleaning chemicals is an industrial solvent called PCE, also known as tetrachloroethylene, perchloroethylene and perc. The Environmental Protection Agency considers PCE a probable human carcinogen, and it has been linked to bladder cancer, multiple myeloma and non-Hodgkin lymphoma.Follow Climate & environmentLast year, the EPA announced a new rule banning PCE for most uses and giving dry cleaners a 10-year phaseout period. The Trump administration is reconsidering this decision, according to an EPA spokesperson.But a recent study found that exposure to PCE tripled the risk of liver fibrosis, excessive scarring that can lead to liver disease and liver cancer. Researchers found that repeated exposure to PCE, which is detectable in an estimated 7 percent of the U.S. population, increased the likelihood of liver damage.“If you’ve been exposed to PCE, talk to your doctor about it,” said Brian P. Lee, associate professor of medicine at the University of Southern California and the study’s lead author.The study found that higher-income households faced the most risk from PCE exposure because they are more likely to use dry cleaning. People who work in cleaning facilities or live nearby also face an elevated risk due to prolonged exposure. Once the chemical gets into a building or the ground, it’s very difficult to remove. The EPA estimates that roughly 6,000 dry cleaners, mostly small businesses, still use PCE in the United States.Lee said the study adds to the growing list of harms associated with the chemical.Studies have also shown that PCE can linger on clothing after dry cleaning and that it builds up over time after repeated cleanings and can contaminate indoor air as it vaporizes.“We now have decades of studies confirming that these widespread dry cleaning chemicals are exposing people to unacceptable risks of cancer and other serious diseases,” said Jonathan Kalmuss-Katz, a senior attorney at the advocacy group Earthjustice. “Those harms are entirely avoidable.”Jon Meijer, director of membership at the Drycleaning & Laundry Institute International, a trade association, said the group supports the original rule passed under the Biden administration and explained that those who still use the chemical do so because of financial challenges.“It’s time for a phaseout of perchloroethylene,” Meijer said. “There are so many alternatives out there.”Safer alternativesExperts say there are plenty of alternatives to using harmful dry cleaning chemicals, but some are safer than others.Go dry-clean free: Try purchasing clothes that don’t need to be dry-cleaned. Selecting cotton blazers and other professional attire, for example, can reduce dry cleaning visits, said Tasha Stoiber, a senior scientist at the Environmental Working Group, an advocacy group. “The easiest thing is to look for professional staples that don’t need to be dry-cleaned,” Stoiber said.Hand-washing: Some “dry-clean only” garments can be delicately hand-washed in cold water with a gentle detergent specific to the particular fabric you’re using. Hanging delicate clothes to dry after a wash can avoid damage from heated air dryers.Steaming: Steam cleaning can freshen up clothes by removing odors, bacteria and small stains without needing a full wash.Commercial wet cleaning: Commercial wet cleaning relies on biodegradable detergents and water instead of toxic solvents.Liquid carbon dioxide: Experts suggest selecting dry cleaners that use liquid carbon dioxide as a solvent to remove dirt and avoid toxic chemicals.Watch out for greenwashingSome businesses advertise eco-friendly or “green” alternatives to dry cleaning. But experts warn that new chemicals can have their own downsides.Diana Ceballos, an assistant professor in the University of Washington’s Department of Environmental and Occupational Health Sciences, said that dry cleaning technology has improved dramatically and that new solvents and machinery can be more effective than PCE.Still, Cebellos said that there can be a lot of “regrettable substitution” when it comes to alternatives to PCE and that some that are billed as “safe” or “organic” could also be toxic.“Most options are far better,” Cebellos said. “But there’s a lot of greenwashing” out there, so people should ask questions and do “a little bit of research.”

Emergency Crews Respond to Ammonia Leak at Mississippi Fertilizer Plant

(Reuters) -Emergency teams responded on Wednesday to a chemical leak, possibly caused by an explosion, at a fertilizer plant in Central Mississippi...

(Reuters) -Emergency teams responded on Wednesday to a chemical leak, possibly caused by an explosion, at a fertilizer plant in Central Mississippi, according to Governor Tate Reeves and media reports. No injuries were immediately reported.A tall cloud of orange vapor could be seen rising over the facility in a photo from the scene of the plant posted online by television station WJTV, a CBS News affiliate in Jackson, Mississippi, the state capital.The governor identified the leaking chemical as anhydrous ammonia, a toxic substance that can cause irritation to the eyes and lungs.Fertilizer manufacturer CF Industries said in statement that "all employees and contractors on site at the time of the incident have been safely accounted for, with no injuries reported."It said it had notified government officials of an "incident" that occurred at its Yazoo City Complex at about 4:25 p.m. CT (2225 GMT).Reeves said in a statement posted on social media that state authorities were "actively responding to the anhydrous ammonia leak" at the plant, located about 50 miles (80.5 km) north of Jackson."Initial reports indicate the leak is due to an explosion. At this time, no deaths or injuries have been reported," the governor said.Personnel from the Mississippi Department of Environmental Quality were among various teams dispatched to the scene, WJTV reported.The governor said residents living along two nearby streets should be evacuated, while other residents in the vicinity were encouraged to shelter in place.(Reporting by Steve Gorman in Los Angeles; Additional reporting by Costas Pita in Los Angeles and Angela Christy in Bengaluru; Editing by Himani Sarkar and Stephen Coates)Copyright 2025 Thomson Reuters.

EPA Proposes Approving Fifth ‘Forever Chemical’ Pesticide

November 5, 2025 – In line with its plan to continue pesticide approvals despite the government shutdown, the Environmental Protection Agency (EPA) announced this week that it will register a new weedkiller for use in corn, soybean, wheat, and canola fields. The herbicide, epyrifenacil, is the fifth pesticide set to be approved by the agency […] The post EPA Proposes Approving Fifth ‘Forever Chemical’ Pesticide appeared first on Civil Eats.

November 5, 2025 – In line with its plan to continue pesticide approvals despite the government shutdown, the Environmental Protection Agency (EPA) announced this week that it will register a new weedkiller for use in corn, soybean, wheat, and canola fields. The herbicide, epyrifenacil, is the fifth pesticide set to be approved by the agency within the last few months that fits into the group of chemicals called PFAS (per- and polyfluoroalkyl substances), based on a commonly used definition. And the agency is moving fast. The first pesticide was proposed for registration in April; that pesticide, called cyclobutrifluram, was finalized today. PFAS are linked to a wide range of health harms and are commonly called “forever chemicals” because they don’t break down easily and they accumulate in soil and water. In 2023, however, the EPA officially adopted a narrower definition. With the proposed approval of epyrifenacil, the agency for the first time has waded into the debate over which pesticides are PFAS and whether concerns voiced over other recent registrations of similar pesticides are warranted. In its announcement, the agency noted that epyrifenacil “contains a fluorinated carbon” and directed the public to a new website where it lays out its position on pesticides that contain fluorinated carbons. Whether those chemicals fit the definition of PFAS doesn’t matter, the agency argues, because under the law, the EPA evaluates the risks of each chemical individually. “Regardless of whether a chemical meets a specific structural definition or is part of a category or class of chemicals, the Agency utilizes a comprehensive assessment process under [the Federal Insecticide, Fungicide, and Rodenticide Act] to evaluate the potential risks of pesticide use,” it said. “This robust, chemical-specific process considers both hazard and exposure in determining whether the pesticide under review may pose risk to human health or the environment.” Epyrifenacil was developed by Japan-based Sumitomo Chemical, which owns Valent U.S.A. in the U.S. It’s one of a new class of herbicides designed to help farmers kill weeds that have developed resistance to popular chemicals like glyphosate. It’s also specifically designed for farmers to spray on cover crops and in no-till systems to prep fields for planting. The pesticide industry has lobbied in recent years to get the EPA to approve new chemicals to address what it calls an “innovation backlog.” Nathan Donley, environmental health science director at the Center for Biological Diversity, said in a statement that an “office run by chemical lobbyists” is whitewashing what is already known about the risks of PFAS. “Not only did the pesticide industry get a proposed approval of its dangerous new product,” he said, “but it also got a shiny new government website parroting its misleading talking points.” (Link to this post.) The post EPA Proposes Approving Fifth ‘Forever Chemical’ Pesticide appeared first on Civil Eats.

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