Lifelong Smokers Rarely Develop Lung Cancer, Scientists May Know Why

The number one risk factor for developing lung cancer is smoking cigarettes, with tobacco products causing roughly 90% of lung cancer deaths in the United States alone. Without a doubt, the best way to protect yourself from lung cancer is to avoid smoking cigarettes, yet, on the other hand, it is also true that many lifelong smokers are not doomed to develop cancer.

Lung Cancer and Smoking: Truth Revealed

Contrary to popular belief, the majority of lifelong smokers do not develop lung cancer. Scientists have always wondered why? Now, a recent study adds weight to the idea that genetics may be behind the mysterious relationship between smoking and lung cancer.

A team of researchers found an inherent advantage among people who frequently smoke but never develop lung cancer. The cells lining their lungs appear less likely to mutate over time.

The findings from the study published in the journal Nature Genetics, titled "Single-cell analysis of somatic mutations in human bronchial epithelial cells in relation to aging and smoking," suggest that DNA repair genes are more active in certain individuals, which protect them against cancers arising, even when cigarettes are smoke regularly.

Researchers used genetic profiles from the bronchi of 14 never-smokers and 19 light, heavy, and moderate smokers. Surface cells gathered in front of the participant's lungs were sequenced individually to measure the mutations in their genomes. Simon Spivack, an epidemiologist, and pulmonologist from the Albert Einsteins College of Medicine, explained that lung cells survive for decades and thus can accumulate mutations with age and smoking. He adds that the samples are among the most likely to become cancerous of all lung cell types.

According to researchers, the findings unequivocally demonstrate that mutations in the lungs of humans increase with natural age, and for smokers, the DNA damage is significantly more.

Tobacco and DNA Damage in the Lungs

For decades, tobacco smoke has been associated with triggering DNA damage in the lung; however, a new study found not all smokers are the same.

While the amount of tobacco a person has smoked was linked to increases in cell mutation rates, after smoking for roughly 23 years with a pack a day, the risks plateau, Spivack says that the heaviest smokers weren't seen to have the highest mutation burden. The study's data suggests that individuals may have survived for so long despite smoking heavily because they managed to suppress further mutation accumulation. This leveling off of mutations could stem from people havering very proficient systems for repairing DNA damage or detoxifying cigarette smoke, reports ScienceAlert.

The study's findings could help explain the reason behind 80 to 90 percent of lifelong smokers never developing lung cancer. It could also help explain why other people who never smoke develop tumors.

Although toxic tobacco smoke triggers extra cell mutations in the person's lungs, whether these mutations develop into tumors depends entirely on how well the body can repair DNA and reduce its damage.

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