Scientists Identify Blood Marker That Detects Lung Cancer Years Earlier

The earliest warning sign of lung cancer may not come from a scan-it could already be circulating in the bloodstream years before the disease appears.

A new study published in Cell has identified a unique blood-based protein signature that can predict a person's risk of developing lung cancer more than five years before diagnosis. The discovery could help doctors identify high-risk individuals much earlier, creating opportunities for prevention before cancer develops.

Researchers analyzed more than 48,000 blood samples and uncovered a pattern involving 14 proteins that consistently predicted future lung cancer risk. The findings were validated across eight independent international datasets and were observed not only in smokers but also in people who had never smoked.

Scientists believe the protein signature does not originate from an existing tumor. Instead, it appears to reflect chronic inflammation and biological changes occurring in the lungs long before cancer becomes detectable. This suggests that lung cancer may be preceded by a previously unrecognized "pre-disease" phase, during which intervention could potentially reduce risk.

Lung cancer remains the leading cause of cancer-related deaths worldwide. One major challenge is that many cases are diagnosed only after symptoms develop, when treatment options are often less effective. Current screening programs primarily focus on older adults with a significant smoking history, leaving many at-risk individuals outside eligibility criteria.

The newly identified blood signature could eventually help expand screening beyond traditional high-risk groups. Researchers say it may also help identify people who could benefit from preventive therapies aimed at stopping cancer before it starts.

The findings add to growing evidence that chronic inflammation may play a key role in the early stages of several age-related diseases. According to the research team, the same biological processes detected in the study may also help explain why certain lung diseases develop years before symptoms appear.

While more studies are needed before the test can be used in clinical practice, the discovery moves scientists closer to a future where lung cancer risk can be detected years in advance.

REFERENCE: Pandya T, Zagorulya M, Leung M, et al.; Plasma signals of lung tumor promotion for molecular cancer prevention; Cell, 2026; DOI: 10.1016/j.cell.2026.05.005