BOSTON — Scientists have identified a rare inherited mutation associated with a sharply increased risk of lung cancer, including among people who have never smoked.
The Dana-Farber Cancer Institute-led study analysed genetic and health information from 3.37 million participants of predominantly European ancestry. Carriers of an inherited EGFR T790M variant had about 25 times the lung-cancer risk of non-carriers overall and roughly 62 times the risk among never-smokers, researchers reported in Science on 17 September.
The variant is uncommon—estimated at about one in 15,000 people in the United States—but appeared more frequently in some Southern Appalachian communities. Researchers found no comparable association with 17 other cancers they examined.
The finding matters for women because lung cancer in never-smokers disproportionately affects women and people of East Asian ancestry. It also challenges the reflex to treat every lung-cancer diagnosis as evidence of tobacco use. Stigma can delay symptoms being taken seriously and can make patients feel responsible for a disease with multiple biological and environmental causes.
The study does not mean every carrier will develop cancer. A relative increase from a low baseline is not the same as certainty, and family history, age, environmental exposures and other genes can all change individual risk.
Nor does the research establish a new screening standard. Low-dose CT screening currently targets defined high-risk groups, mainly based on age and smoking history. Screening people with a rare mutation may eventually be useful, but researchers first need evidence about when scans should begin, how often to repeat them and whether early detection reduces deaths without causing excessive false alarms and unnecessary procedures.
The ancestry limits are also important. A dataset dominated by people of European descent cannot determine how often the variant occurs or behaves in every population. Follow-up work should include regions where never-smoker lung cancer is more common and report outcomes by sex without assuming that biological sex explains every observed difference.
People with a strong family history of lung cancer should discuss it with a qualified clinician or genetics service rather than ordering an unvalidated direct-to-consumer test. The discovery is a promising route toward risk-based care, not a reason for panic or self-diagnosis.
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