Cancer Say: kan-ser Cancer is a disease that happens when the body makes cells that are not normal. These cells grow very quickly to take over the normal cells and can spread to different parts of the body if a doctor doesn't treat it. People can get very sick from cancer and even die. There are many different types of cancer, but you can't get any of them from being near someone who has it. But you can get some kinds of cancer from smoking, so that's another good reason to say no to cigarettes! Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.