Most people don't usually associate cancer with teens. Cancer is
more common in adults, so it's likely that you know someone who
has had it, such as an older relative or someone in a friend's
family. But teens can get some types of cancer, too. Read on to
learn about cancer and how it's treated. What Is Cancer? The
word cancer actually refers to many diseases, not one. In fact,
there are more than 100 types of diseases known collectively as
cancer. What they all have in common is the overgrowth of cells,
tiny units that make up all living things. Cancer (also known as
malignancy, pronounced: muh-lig-nun-see) occurs when cells begin
to grow and multiply in an uncontrolled way. Normal body cells
grow and divide over a period of time until they eventually die.
But cancer cells continue to grow and divide and grow and
divide. Eventually, they gather to form tumors. Tumors
(pronounced: too-murz) are lumps that can interfere with the
body's normal processes. Sometimes cells from a tumor break away
and travel to a d