Tissue Procurement and Natural History Study of People With Non-Small Cell Lung Cancer, Small Cell Lung Cancer, Extrapulmonary Small Cell Cancer, Pulmonary Neuroendocrine Tumors, and Thymic Epithelial Tumors

Background: \- Lung cancer is the leading cause of cancer-related death worldwide. It causes more than one million deaths every year. Researchers want to gather tissue samples from people with lung and thymic cancers to understand the disease better. This may lead to new ways to diagnose and treat it. Objective: \- To collect tissue samples for use in the study of lung cancers. Eligibility: \- Adults over age 18 with non-small cell lung cancer, small cell lung cancer, extra pulmonary small cell cancer, pulmonary neuroendocrine tumors, and thymic epithelial tumors. Design: * Participants will be screened with a medical history, physical exam, and blood tests. They will be asked about how they perform their daily tasks. * Participants may be asked to give urine and blood samples. They may give a saliva sample if they cannot give blood. They will also give a sample of their tumor from a biopsy they had. They may also be given the option to undergo a biopsy. * Participants may have MRI, CT, and/or PET scans of the body. They will lie in a machine that takes pictures of the body. * After visits to the Clinical Center end, researchers will contact participants by phone every year to check on their health.