What Is Cancer?

It starts with cells

Cells are the "building blocks" of your body. When you are healthy, cells grow and divide to make new cells whenever your body needs them. Old cells die and new cells take their place.

Sometimes, something happens to make this process go wrong. New cells form that are not needed; old cells don't die when they should. Extra cells (both new and old) can turn into a growth that's also called a tumor.

Tumors can be:

  • noncancerous - also called "benign"
  • cancerous - also called "malignant"

Cells from a cancerous tumor can spread, invading and damaging nearby areas of the body. They can also leave the tumor and travel through the blood or the lymph system to form new tumors in other parts of the body.

Benign
Not cancerous.
Cancer
A general term for more than 100 different diseases that involve the uncontrolled increase of abnormal new cells. These cells form tumors that can destroy surrounding tissue and spread throughout the body.
Cell
The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.
Lymph
The almost colorless fluid that travels through the lymphatic system and carries cells that help fight infection and disease.
Malignant
Cancerous; cells that can invade and destroy nearby tissue and spread to other parts of the body.
Tumor
An abnormal mass of tissue that results from excessive cell division. Tumors perform no useful body function. They may either be benign (not cancerous) or malignant (cancerous).

How Do You Know?

What are the signs of melanoma?

Help in Many Places

Learn about professionals who can help you with the strain of coping with disease and treatment.