Lung cancer is the most common cause of cancer death in the US in both men and women. This research study will enroll lung cancer patients into a registry to study changes in DNA (or genetic material) that may be associated with development of lung cancer or other lung diseases such as chronic obstructive pulmonary disease (COPD). We will also study the role of eating habits on lung cancer diagnosis and treatment, as well as the effects of the disease and treatment on quality of patient's lives.