Lung cancer is commonly associated with smoking. However, among people diagnosed with lung cancer, the proportion who have never smoked has been increasing, and there are many reasons why a person who has never smoked may develop this disease. Lori Sakoda, PhD, MPH, ATSF, a research scientist and epidemiologist at Kaiser Permanente Northern California, explains what factors may come into play, what the ongoing research shows, and what knowledge gaps exist on this topic. Patti Tripathi hosts.