is when cells in the body change and grow out of control. To help you understand what
happens when you have cancer, let's look at how your body works normally. Your body is
made up of tiny building blocks called cells. Normal cells grow when your body needs
them, and die when your body doesn't need them any more.
Cancer is made up of abnormal cells that grow even though your body doesn't need them.
In most cancers, the abnormal cells grow to form a lump or mass called a tumor. If
cancer cells are in the body long enough, they can grow into (invade) nearby areas. They
can even spread to other parts of the body (metastasize).