Cancer is a group of related diseases in which cells divide uncontrollably. These abnormal cells form growths called tumors. Benign tumors do not spread beyond their original location, but they can occupy more space as they grow. Malignant tumors can spread to other parts of the body and invade organs and tissues. Once cancer has spread, it may be harder to treat.
Uncontrolled cell growth causes cancer. Once cells have become old or outlived their purpose, the body destroys them through a process of programmed cell death, called apoptosis. A combination of factors, including gene changes and environmental exposures, can disrupt this normally orderly process.
Some cancers run in families. In part, this is due to genetic changes, or mutations....Read more