Lung cancer is a common cause of cancer deaths in non-smoking individuals worldwide. However, since lung cancer is primarily viewed as a smoker¹s disease, the risk of non-smokers developing lung cancer is often overlooked, leading to delays in diagnosis and treatment. We propose that lung cancer in non-smokers develops through mechanisms different from those induced by tobacco carcinogens. The goal of our study is to determine the mutations and genes involved in the development of lung cancer specifically in non-smokers, in order to identify genes and pathways that are specifically disrupted in non-smoker tumours. By discovering causal events and key functions disrupted during cancer development in non-smokers, we will identify targets for developing diagnostic and therapeutic strategies for lung cancer in non-smokers.