Cancer describes an enormous spectrum of diseases that all originate from uncontrolled cellular growth. Broadly divided into benign tumors (unable to metastasize) or malignant tumors (able to invade normal tissues), cancers are further defined and classified by their cell type, tissue, or organ of origin. Cancer remains the number two cause of death in the U.S., second only to heart disease, and the Intramural Research Program (IRP) is committed to advancing research, building expertise, and leveraging resources to address this global challenge. Our scientists are constantly learning more about the causes of cancer, and developing new and better ways to prevent, detect, and treat it.