Lung Cancer in Never Smokers: Genetics, Exposures, and Distinct Immune Landscape

Lung cancer in never smokers (LCINS) disproportionately affects younger women and East Asian populations and is characterized by distinct genetic susceptibility, environmental exposures, and molecular alterations. However, never smokers remain excluded from current screening guidelines despite rising incidence and identifiable high-risk subgroups. Family history confers substantial risk, with affected first-degree relatives showing 1.7-fold higher incidence, while genome-wide association studies and polygenic risk scores further refine genetic susceptibility.