ACS (American Cancer Society): A "nationwide community-based voluntary health organization dedicated to eliminating cancer as a major health problem by preventing cancer, saving lives and diminishing suffering from cancer through research, education, advocacy, and service."

The American Cancer Society is one of the oldest and largest voluntary health agencies in the United States. It is the largest source of private, nonprofit cancer research funds in the United States. The Society is headquartered in Atlanta, Georgia, with state Divisions and more than 3,400 local Units. The Society's prevention programs focus on tobacco control, sun protection, diet and nutrition, comprehensive school health education, early detection, and treatment. A variety of service and rehabilitation programs are available to patients and their families.