What is cancer?

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Brooke Rosenbaum
OncoLink
Last Modified: October 21, 2011

Cancer is the general name for a group of over 100 diseases that arise from uncontrolled cell growth. Cells are the smallest units of life that make up the tissues of our bodies. They grow and divide in a highly controlled manner to maintain the right amount of cells to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells. If this regulated system is disrupted, cells may not grow at the pace they are supposed to or die when they should. If cells start growing out of control, the extra cells may form a mass called a tumor. Tumors can grow or spread to other areas of the body. Cancers are harmful to our bodies because tumors can put pressure on vital organs and cause them to fail, or they can rob nutrients from other healthy cells.

The SCIENCE OF CANCER 101 resource will provide a detailed picture of the causes, course, and treatments of cancer. Through easy-to understand-explanations, helpful links, videos, and visuals, we hope to paint a picture of what is happening inside your (or a loved one's) body.

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Comprehensive overview of cancer biology from CancerQuest

Learn More

CancerQuest: Defining cancer
National Cancer Institute: What is cancer?
American Cancer Society: What is cancer?

How do healthy cells work? »