Many people think of lung cancer as a disease that mostly affects smokers.
But recently, more and more people who have never smoked are being diagnosed with lung cancer. This increase is especially seen in women and in East Asian countries.
A new international study published in the journal Nature has uncovered some important reasons why this is happening. Scientists from the University of California San Diego and the U.S. National Cancer Institute led the study.
They looked at the DNA of lung tumors from 871 people who had never smoked. These people lived in 28 different regions around the world, with different levels of air pollution.
The researchers used a special method called whole-genome sequencing to find patterns of DNA damage in the tumors. These patterns, called “mutational signatures,” show what kind of harmful substances the cells have been exposed to.
The results were surprising. People living in areas with more air pollution had many more harmful mutations in their lung tumors. Some of these mutations were the same as those found in people who smoke heavily.
One shocking finding was that people who had never smoked still had a fourfold increase in a mutation usually caused by tobacco. There was also an increase in mutations related to aging, which means that pollution may speed up aging in lung cells.
The study found a clear pattern—the more air pollution someone was exposed to, the more mutations their lung cancer had. The tumors also had shorter telomeres, which are protective caps at the ends of chromosomes. Shorter telomeres are a sign of cell damage and aging.
The researchers also looked at people who had been exposed to secondhand smoke. These people had shorter telomeres too, but their tumors didn’t show the same number of mutations as those exposed to air pollution.
This suggests that secondhand smoke may be harmful in different ways or that we don’t yet have the right tools to measure all the damage it causes.
Another big discovery was about a substance called aristolochic acid. This chemical is found in some traditional Chinese herbal medicines and is known to cause cancer in the liver, kidneys, and bladder. This study is the first to link it to lung cancer.
The mutations from aristolochic acid were mainly found in people from Taiwan who had never smoked. Scientists believe that breathing in herbal remedies might be the cause, but more research is needed.
One of the most interesting findings was a completely new mutation pattern found only in people who never smoked. It wasn’t connected to air pollution, herbal medicine, or any known cause. Scientists don’t yet know what is causing it, but they plan to study it more.
This research is part of a global effort to understand why lung cancer is affecting more non-smokers. The team plans to expand their research to include people from Latin America, the Middle East, and other parts of Africa. They also want to study other possible causes like marijuana, e-cigarettes, radon gas, and asbestos.
This study is a big step forward in understanding how our environment affects our lungs. It shows how important clean air is and why we need to be careful with traditional remedies that might contain harmful chemicals. It also highlights the need to find out more about how different things in our surroundings can harm our DNA and health.
As Dr. Maria Teresa Landi from the National Cancer Institute said, this discovery is not just about science—it’s a chance to protect people from getting cancer before it starts.
If you care about lung health, please read studies that many smokers have undetected lung diseases and why vitamin K is very important for you lung health.
For more health information, please read studies about New diabetes drugs can benefit your kidney and lung health and the link between cough and lung cancer.
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