Rare gene variant raises lung cancer risk in non-smokers
Lung cancer increasingly affects people who have never smoked. Scientists have been searching for the reasons for years. Now a rare genetic variant has been found that dramatically raises the risk in non-smokers.
A team of scientists identified a genetic variant associated with a 25-fold higher risk of lung cancer in people who have never smoked. The researchers reported the finding in the journal Science, drawing on genetic data from millions of people collected by 23andMe. In the United States, the variant is significantly more common among people from the Southern Appalachia region than elsewhere in the country.
Rare, but revealing
The variant is uncommon: it accounts for only a small fraction of all lung cancer cases in never-smokers. Experts emphasise this point. Nevertheless, the discovery matters for two reasons. First, it confirms that lung cancer in never-smokers has different risk factors from smoker-related lung cancer. Those tumours may require a different approach to screening and treatment. Second, the study demonstrates what insights are possible with large-scale genetic datasets.
From a longevity perspective, the research is relevant in terms of prevention. Lung cancer is one of the leading causes of premature death. If genetic variants determine who is at elevated risk, that opens the door to more targeted screening for people who consider themselves low-risk because they have never smoked.
Caution in interpretation
The study has limitations. The data partly come from self-reporting and commercial genetic tests, which affects precision. Furthermore, a 25-fold increased risk for an already rare condition still represents a low absolute risk. This is an association, not proven causation. Whether the variant directly causes lung cancer, or is linked to another underlying factor, has not yet been established.
What the study does show is that never-smokers with lung cancer are not a homogeneous group. Genetic risk factors, environmental exposures, and unknown variables all play a role. That calls for a more nuanced approach to risk prediction.
Search terms for further research: lung cancer genetic risk never-smokers, rare genetic variants cancer risk population study, lung carcinoma non-smoker risk factors