Lung cancer is the leading cause of cancer-related mortality for men and women in the United States, accounting for 28% of all cancer deaths in 2004. Non-small cell lung cancer, or NSCLC, is the most common tissue type of lung cancer. A detailed knowledge of the spectrum of genetic mutations responsible for causing NSCLC is important in order to develop new methods of diagnosing and treating this disease. Lung cancer chromosomes typically exhibit widespread structural abnormalities leading to amplifications and deletions of genetic material relevant to cancer formation. Genetic analyses to date have begun to catalog the types of chromosomal gains and losses that are the hallmark of lung cancer. The goal of this study is to use a new technique to systematically study the entire gene structure (genome) of lung cancer cells to identify recurring small regions of chromosomal gains and losses. Genes located in newly identified regions of chromosomal abnormality will then be tested for their role in lung cancer development. Identification of new lung cancer genes will lead to improved understanding of the genetic changes involved in the development of lung cancer and suggest new avenues for treatment.