Never smoking does not translate to no risk of lung cancer. Lung cancer in never smokers is a growing global health challenge and researchers at University College in London say the disease is biologically distinct from smoking related lung cancer. Patients and their healthcare providers may overlook some symptoms simply because there is no history of smoking. Vague symptoms such as coughing, fatigue and difficulty swallowing may easily be attributable to benign conditions. Authors of the study in the journal Trends in Cancer call for greater symptom awareness because of rapidly evolving evidence on who is at risk and how lung cancer in non-smokers develops. Among their recommendations: be aware of inflammation caused by air pollution and second-hand smoke.